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  • Access class instance "name" dynamically in Python

    - by user328317
    In plain english: I am creating class instances dynamically in a for loop, the class then defines a few attributes for the instance. I need to later be able to look up those values in another for loop. Sample code: class A: def init(self, name, attr): self.name=name self.attr=attr names=("a1", "a2", "a3") x=10 for name in names: name=A(name, x) x += 1 ... ... ... for name in names: print name.attr How can I create an identifier for these instances so they can be accessed later on by "name"? I've figured a way to get this by associating "name" with the memory location: class A: instances=[] names=[] def init(self, name, attr): self.name=name self.attr=attr A.instances.append(self) A.names.append(name) names=("a1", "a2", "a3") x=10 for name in names: name=A(name, x) x += 1 ... ... ... for name in names: index=A.names.index(name) print "name: " + name print "att: " + str(A.instances[index].att) This has had me scouring the web for 2 days now, and I have not been able to find an answer. Maybe I don't know how to ask the question properly, or maybe it can't be done (as many other posts seemed to be suggesting). Now this 2nd example works, and for now I will use it. I'm just thinking there has to be an easier way than creating your own makeshift dictionary of index numbers and I'm hoping I didn't waste 2 days looking for an answer that doesn't exist. Anyone have anything? Thanks in advance, Andy Update: A coworker just showed me what he thinks is the simplest way and that is to make an actual dictionary of class instances using the instance "name" as the key.

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  • What tasks aren't easy for PHP, ColdFusion and ASP?

    - by boost
    PHP, ColdFusion, and ASP (among many others) are usually sold on their strengths. What are their weaknesses? If one were to develop a niche product to handle the things that these products weren't so good at, what should it focus on? EDIT I'm trying to figure out what things PHP etc are bad at. They're all good at doing the nuts and bolts stuff, if one is looking with a bottom-to-top mindset. I'm thinking a little more globally, more top-to-bottom; what's difficult to achieve in PHP/ASP/CF without thousands of lines of code and twenty minutes of server time? EDIT Suppose company A comes up to you and says, "We want you to do x in PHP." What values of x will cause you to say, "Forget it, buddy, no one in their right mind would use PHP for that"? (swap PHP in the above quote for your favourite tool) EDIT Have we got to the point where everyone's needs can be met with PHP frameworks, Rails and ... er ... Java?

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  • Image insert problem php sqlserver

    - by Termedi
    Hi I can not save image inside a sql server 2000 database. datatype is image here is the code: // Image Upload <?php include('config.php'); if(is_uploaded_file($_FILES['userfile']['tmp_name'])) { $fileName = $_FILES['userfile']['name']; $tmpName = $_FILES['userfile']['tmp_name']; $fileSize = $_FILES['userfile']['size']; $fileType = $_FILES['userfile']['type']; $size = filesize($tmpName); set_magic_quotes_runtime(0);//to desactive the default escape spacials caracters made by PHP in the externes files $img_binaire = base64_encode(fread(fopen(str_replace("'","''",$tmpName), "r"), $size)); $query = "INSERT INTO test_image (image_name, image_content, image_size) ". "VALUES ('{$fileName}','{$img_binaire}', '{$size}')"; odbc_exec($conn, $query) or die('Error, query failed'); echo "<br>File $fileName uploaded<br>"; echo "<br>File Size: $fileSize <br>"; } ?> // Image Show <?php include('config.php'); $sql = "select * from test_image where id =2"; $rsl = odbc_exec($conn, $sql); $image_info = odbc_fetch_array($rsl); //$count = sizeof($image_info['image_content']); //header('Accept-Ranges: bytes'); //header('Content-Length: '.$image_info['image_size']); //header("Content-length: 17397"); header('Content-Type: image/jpeg'); echo base64_decode($image_info['image_content']); //echo bindec($image_info['image_content']); ?> Error: Warning: odbc_exec() [function.odbc-exec]: SQL error: [Microsoft][ODBC SQL Server Driver][SQL Server]Operand type clash: text is incompatible with image, SQL state 22005 in SQLExecDirect in C:\xampp\htdocs\test\upload.php on line 25 Error, query failed

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  • LinqToSQL not updating database

    - by codegarten
    Hi. I created a database and dbml in visual studio 2010 using its wizards. Everything was working fine until i checked the tables data (also in visual studio server explorer) and none of my updates were there. using (var context = new CenasDataContext()) { context.Log = Console.Out; context.Cenas.InsertOnSubmit(new Cena() { id = 1}); context.SubmitChanges(); } This is the code i am using to update my database. At this point my database has one table with one field (PK) named ID. *INSERT INTO [dbo].Cenas VALUES (@p0) -- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [1] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1* This is LOG from the execution (printed the context log into the console). The problem i'm having is that these updates are not persistent in the database. I mean that when i query my database (visual studio server explorer - new query) i see the table is empty, every time. I am using a SQL Server database file (.mdf).

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  • ASP.NET: ModalPopupExtender prevents button click event from firing

    - by C. Griffin
    Here is what I'm trying to do: Click a button on my page, which in turn makes (2) things happen: Display a ModalPopup to prevent the user from pressing any buttons or changing values Call my code behind method, hiding the ModalPopup when finished Here is the ASP markup: <asp:UpdatePanel ID="UpdatePanel2" runat="server" ChildrenAsTriggers="true" UpdateMode="Always"> <Triggers> <asp:AsyncPostBackTrigger ControlID="btnSaveData" EventName="Click" /> </Triggers> <ContentTemplate> <asp:Panel ID="pnlHidden" runat="server" style="display: none;"> <div> <h1>Saving...</h1> </div> </asp:Panel> <cc1:ModalPopupExtender ID="modalPopup" BackgroundCssClass="modalBackground" runat="server" TargetControlID="btnSaveData" PopupControlID="pnlHidden"> </cc1:ModalPopupExtender> <asp:Button ID="btnSaveData" runat="server" Text="Save Data" OnClick="btnSaveData_Click" /> </ContentTemplate> </asp:UpdatePanel> Now, here is my code behind C# code: protected void btnSaveData_Click(object sender, EventArgs e) { UpdateUserData(GetLoggedInUser()); modalPopup.Enabled = false; } Why doesn't this work? The ModalPopup displays perfectly, but the btnSaveData_Click event NEVER fires.

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  • Django: Filtering datetime field by *only* the year value?

    - by unclaimedbaggage
    Hi folks, I'm trying to spit out a django page which lists all entries by the year they were created. So, for example: 2010: Note 4 Note 5 Note 6 2009: Note 1 Note 2 Note 3 It's proving more difficult than I would have expected. The model from which the data comes is below: class Note(models.Model): business = models.ForeignKey(Business) note = models.TextField() created = models.DateTimeField(auto_now_add=True) updated = models.DateTimeField(auto_now=True) class Meta: db_table = 'client_note' @property def note_year(self): return self.created.strftime('%Y') def __unicode__(self): return '%s' % self.note I've tried a few different ways, but seem to run into hurdles down every path. I'm guessing an effective 'group by' method would do the trick (PostGres DB Backend), but I can't seem to find any Django functionality that supports it. I tried getting individual years from the database but I struggled to find a way of filtering datetime fields by just the year value. Finally, I tried adding the note_year @property but because it's derived, I can't filter those values. Any suggestions for an elegant way to do this? I figure it should be pretty straightforward, but I'm having a heckuva time with it. Any ideas much appreciated.

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  • Conversion failed when converting the varchar value to int

    - by onedaywhen
    Microsoft SQL Server 2008 (SP1), getting an unexpected 'Conversion failed' error. Not quite sure how to describe this problem, so below is a simple example. The CTE extracts the numeric portion of certain IDs using a search condition to ensure a numeric portion actually exists. The CTE is then used to find the lowest unused sequence number (kind of): CREATE TABLE IDs (ID CHAR(3) NOT NULL UNIQUE); INSERT INTO IDs (ID) VALUES ('A01'), ('A02'), ('A04'), ('ERR'); WITH ValidIDs (ID, seq) AS ( SELECT ID, CAST(RIGHT(ID, 2) AS INTEGER) FROM IDs WHERE ID LIKE 'A[0-9][0-9]' ) SELECT MIN(V1.seq) + 1 AS next_seq FROM ValidIDs AS V1 WHERE NOT EXISTS ( SELECT * FROM ValidIDs AS V2 WHERE V2.seq = V1.seq + 1 ); The error is, 'Conversion failed when converting the varchar value 'RR' to data type int.' I can't understand why the value ID = 'ERR' should be being considered for conversion because the predicate ID LIKE 'A[0-9][0-9]' should have removed the invalid row from the resultset. When the base table is substituted with an equivalent CTE the problem goes away i.e. WITH IDs (ID) AS ( SELECT 'A01' UNION ALL SELECT 'A02' UNION ALL SELECT 'A04' UNION ALL SELECT 'ERR' ), ValidIDs (ID, seq) AS ( SELECT ID, CAST(RIGHT(ID, 2) AS INTEGER) FROM IDs WHERE ID LIKE 'A[0-9][0-9]' ) SELECT MIN(V1.seq) + 1 AS next_seq FROM ValidIDs AS V1 WHERE NOT EXISTS ( SELECT * FROM ValidIDs AS V2 WHERE V2.seq = V1.seq + 1 ); Why would a base table cause this error? Is this a known issue? UPDATE @sgmoore: no, doing the filtering in one CTE and the casting in another CTE still results in the same error e.g. WITH FilteredIDs (ID) AS ( SELECT ID FROM IDs WHERE ID LIKE 'A[0-9][0-9]' ), ValidIDs (ID, seq) AS ( SELECT ID, CAST(RIGHT(ID, 2) AS INTEGER) FROM FilteredIDs ) SELECT MIN(V1.seq) + 1 AS next_seq FROM ValidIDs AS V1 WHERE NOT EXISTS ( SELECT * FROM ValidIDs AS V2 WHERE V2.seq = V1.seq + 1 );

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  • SharePoint: Filtering a List that has Folders

    - by Gary McGill
    I have a SharePoint document library that has a folder structure used for organizing the documents (but also for controlling access, via permissions on the folders). The documents in the library are updated every month, and we store every month's version of the document in the same folder; there's a "month" column used for filtering that will contain values like Jan 09, Feb 09, etc. It looks like this: Title Month ----- ----- SubFolder 1 SubFolder 2 [] Interesting Facts Jan 09 [] Interesting Facts Feb 09 [] Interesting Facts Mar 09 [] Fascinating Numbers Jan 09 [] Fascinating Numbers Feb 09 ... Now, because users will generally be most interested in the 'current' month, I'd like them to be able to apply a filter, and select (say) Mar 09. However, if they do this using the built-in filtering, it also filters out the folders, and they can no longer navigate the folder hierarchy. This is no good - I want them to be able to move between folders with the filter intact, so that they don't need to keep switching it off and on again. I figured I might be able to use a custom view (selecting where type=folder or month=[month]), and to an extent that does work. However, I can only get it to work for a fixed month, whereas I need the user to be able to select the month - perhaps via a drop-down control on the page (and I don't want to create 60 views for 5 years' worth of months, nor do I want to have to create a new view every month). I thought it might be possible to create a view in code (rather than via the UI), but I've not been able to figure out how to get a dynamic value (a user-specific setting) into the CAML query. Any pointers gratefully appreciated! And by the way, I am aware of the dogma that folders are bad, and that everything should just be a list. However, having considered the alternatives, I still favour using folders - if I can solve this problem. Thanks in advance.

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  • Byte-Pairing for data compression

    - by user1669533
    Question about Byte-Pairing for data compression. If byte pairing converts two byte values to a single byte value, splitting the file in half, then taking a gig file and recusing it 16 times shrinks it to 62,500,000. My question is, is byte-pairing really efficient? Is the creation of a 5,000,000 iteration loop, to be conservative, efficient? I would like some feed back on and some incisive opinions please. Dave, what I read was: "The US patent office no longer grants patents on perpetual motion machines, but has recently granted at least two patents on a mathematically impossible process: compression of truly random data." I was not inferring the Patent Office was actually considering what I am inquiring about. I was merely commenting on the notion of a "mathematically impossible process." If someone has, in some way created a method of having a "single" data byte as a placeholder of 8 individual bytes of data, that would be a consideration for a patent. Now, about the mathematically impossibility of an 8 to 1 compression method, it is not so much a mathematically impossibility, but a series of rules and conditions that can be created. As long as there is the rule of 8 or 16 bit representation of storing data on a medium, there are ways to manipulate data that mirrors current methods, or creation by a new way of thinking.

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  • Convert Google Analytics cookies to Local/Session Storage

    - by David Murdoch
    Google Analytics sets 4 cookies that will be sent with all requests to that domain (and ofset its subdomains). From what I can tell no server actually uses them directly; they're only sent with __utm.gif as a query param. Now, obviously Google Analytics reads, writes and acts on their values and they will need to be available to the GA tracking script. So, what I am wondering is if it is possible to: rewrite the __utm* cookies to local storage after ga.js has written them delete them after ga.js has run rewrite the cookies FROM local storage back to cookie form right before ga.js reads them start over Or, monkey patch ga.js to use local storage before it begins the cookie read/write part. Obviously if we are going so far out of the way to remove the __utm* cookies we'll want to also use the Async variant of Analytics. I'm guessing the down vote was because I didn't ask a question. DOH! My questions are: Can it be done as described above? If so, why hasn't it been done? I have a default HTML/CSS/JS boilerplate template that passes YSlow, PageSpeed, and Chrome's Audit with near perfect scores. I'm really looking for a way to squeeze those remaining cookie bytes from Google Analytics in browsers that support local storage.

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  • Update Azure Service Configuration File using Powershell

    - by David Osborn
    I'm trying to write a powershell script that updats each of the DiagnosticsConnectionString and DataConnectionString values below, but I can't seem to find each individual Role node using $serviceconfig.ServiceConfiguration.SelectSingleNode("Role[@name='MyService_WorkerRole']") doing echo $serviceconfig.ServiceConfiguration.Role lists out both Role nodes for me so I know it is working up to that point, but after that I am not having much success. where $serviceConfig contains the below XML: <?xml version="1.0"?> <ServiceConfiguration serviceName="MyService" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration"> <Role name="MyService_WorkerRole"> <Instances count="1" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="really long string" /> <Setting name="DataConnectionString" value="really long string 2" /> </ConfigurationSettings> </Role> <Role name="MyService_WebRole"> <Instances count="1" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="really long string 3" /> <Setting name="DataConnectionString" value="really long string 4" /> </ConfigurationSettings> </Role> </ServiceConfiguration>

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  • Joining Tables Based on Foreign Keys

    - by maestrojed
    I have a table that has a lot of fields that are foreign keys referencing a related table. I am writing a script in PHP that will do the db queries. When I query this table for its data I need to know the values associated with these keys not the key. How do most people go about this? A 101 way to do this would be to query this table for its data including the foreign keys and then query the related tables to get each key's value. This could be a lot of queries (~10). Question 1: I think I could write 1 query with a bunch of joins. Would that be better? This approach also requires the querying script to know which table fields are foreign keys. Since I have many tables like this but all with different fields, this means writing nice generic functions is hard. MySQL InnoDB tables allow for foreign constraints. I know the database has these set up correctly. Question 2: What about the idea of querying the table and identifying what the constraints are and then matching them up using whatever process I decide on from Question 1. I like this idea but never see it being used in code. Makes me think its not a good idea for some reason. I would use something like SHOW CREATE TABLE tbl_name; to find what constraints/relationships exist for that table. Thank you for any suggestions or advice.

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  • Membership.Updateuser not really updating the database.

    - by Shimrod
    Hi everybody, I'm currently working on a membership system for my web application, which is based on forms authentication from the framework. I created some users with the integrated tool, and the login is perfectly working. But now what I want to do is to give administrator the capability to create, modify, delete users. So here is what I've got right now: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim muc As MembershipUserCollection = Membership.GetAllUsers() ComboBox1.DataSource = muc ComboBox1.DataValueField = "UserName" ComboBox1.DataTextField = "UserName" ComboBox1.DataBind() End Sub Protected Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles ComboBox1.SelectedIndexChanged Dim userName As String = ComboBox1.SelectedValue Dim mu As MembershipUser = Membership.GetUser(userName) Dim userRoles As String() = Roles.GetRolesForUser(userName) tbComments.Text = mu.Comment tbEmail.Text = mu.Email lblUserName.Text = mu.UserName End Sub Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click Dim userName As String = ComboBox1.SelectedValue Dim mu As MembershipUser = Membership.GetUser(userName) If Not mu Is Nothing Then Try mu.Comment = tbComments.Text Membership.UpdateUser(mu) mu.Email = tbEmail.Text Membership.UpdateUser(mu) mu.IsApproved = True Membership.UpdateUser(mu) mu = Nothing Catch ex As Exception Console.WriteLine(ex.ToString()) End Try End If DetailPanel.Visible = False End Sub The problem is that the record doesn't seem to be updated in the database. I made the multiple calls to Membership.UpdateUser after reading this blog entry, but it didn't change anything. A strange think I noticed while debugging, is that when I enter the Button1_Click method, Membership.GetUser(userName) returns me values from my precedent attempt ! I don't really understand what I'm missing. Does someone have a clue ? Thanks in advance !

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  • C# : Forcing a clean run in a long running SQL reader loop?

    - by Wardy
    I have a SQL data reader that reads 2 columns from a sql db table. once it has done its bit it then starts again selecting another 2 columns. I would pull the whole lot in one go but that presents a whole other set of challenges. My problem is that the table contains a large amount of data (some 3 million rows or so) which makes working with the entire set a bit of a problem. I'm trying to validate the field values so i'm pulling the ID column then one of the other cols and running each value in the column through a validation pipeline where the results are stored in another database. My problem is that when the reader hits the end of handlin one column I need to force it to immediately clean up every little block of ram used as this process uses about 700MB and it has about 200 columns to go through. Without a full Garbage Collect I will definately run out of ram. Anyone got any ideas how I can do this? I'm using lots of small reusable objects, my thought was that I could just call GC.Collect() on the end of each read cycle and that would flush everything out, unfortunately that isn't happening for some reason.

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  • Unable to turn off notice errors in PHP 5.3.2

    - by knkk
    Hi everyone, I recently migrated to PHP 5.3.2, and realized that I am unable to turn off notice errors in my site now. I went to php.ini, and in these lines: ; Common Values: ; E_ALL & ~E_NOTICE (Show all errors, except for notices and coding standards warnings.) ; E_ALL & ~E_NOTICE | E_STRICT (Show all errors, except for notices) ; E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR (Show only errors) ; E_ALL | E_STRICT (Show all errors, warnings and notices including coding standards.) ; Default Value: E_ALL & ~E_NOTICE ; Development Value: E_ALL | E_STRICT ; Production Value: E_ALL & ~E_DEPRECATED ; http://php.net/error-reporting error_reporting = E_ALL & ~E_NOTICE ...I've tried setting everything (and I restart apache each time), but I am unable to get rid of notices. The only way I'm able to get rid of notice errors is by setting : display_errors = Off That is, of course, not something I can do since I need to see errors to fix them, and I would like to see errors on the webpage that I am coding rather than log them somewhere. Can someone help? Is this a bug in PHP 5.3.2 or something I am doing wrong? Thank you very much for your time! P. S. Also, would anyone know how I can get PHP 5.3.2 to support the .php3 extension?

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  • Setting up relations/mappings for a SQLAlchemy many-to-many database

    - by Brent Ramerth
    I'm new to SQLAlchemy and relational databases, and I'm trying to set up a model for an annotated lexicon. I want to support an arbitrary number of key-value annotations for the words which can be added or removed at runtime. Since there will be a lot of repetition in the names of the keys, I don't want to use this solution directly, although the code is similar. My design has word objects and property objects. The words and properties are stored in separate tables with a property_values table that links the two. Here's the code: from sqlalchemy import Column, Integer, String, Table, create_engine from sqlalchemy import MetaData, ForeignKey from sqlalchemy.orm import relation, mapper, sessionmaker from sqlalchemy.ext.declarative import declarative_base engine = create_engine('sqlite:///test.db', echo=True) meta = MetaData(bind=engine) property_values = Table('property_values', meta, Column('word_id', Integer, ForeignKey('words.id')), Column('property_id', Integer, ForeignKey('properties.id')), Column('value', String(20)) ) words = Table('words', meta, Column('id', Integer, primary_key=True), Column('name', String(20)), Column('freq', Integer) ) properties = Table('properties', meta, Column('id', Integer, primary_key=True), Column('name', String(20), nullable=False, unique=True) ) meta.create_all() class Word(object): def __init__(self, name, freq=1): self.name = name self.freq = freq class Property(object): def __init__(self, name): self.name = name mapper(Property, properties) Now I'd like to be able to do the following: Session = sessionmaker(bind=engine) s = Session() word = Word('foo', 42) word['bar'] = 'yes' # or word.bar = 'yes' ? s.add(word) s.commit() Ideally this should add 1|foo|42 to the words table, add 1|bar to the properties table, and add 1|1|yes to the property_values table. However, I don't have the right mappings and relations in place to make this happen. I get the sense from reading the documentation at http://www.sqlalchemy.org/docs/05/mappers.html#association-pattern that I want to use an association proxy or something of that sort here, but the syntax is unclear to me. I experimented with this: mapper(Word, words, properties={ 'properties': relation(Property, secondary=property_values) }) but this mapper only fills in the foreign key values, and I need to fill in the other value as well. Any assistance would be greatly appreciated.

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  • Reporting Services - can't group by a column called "LanguageId"

    - by marc_s
    Folks, I have a really odd behavior here: I have a SQL Server 2008 Reporting Services report which gets grouped and sorted dynamically. One of the column in my data set which I display is called LanguageId and I was trying to get a grouping going by this LanguageId field. I checked, double-checked and triple-checked the data being returned - it does contain my expected values for LanguageId and everything seems fine and dandy. It just never worked - I didn't get the expected groups, I got things like a specific node actually changing its display value from one ID to another when expanding its subitems, and other really whacky stuff. I discovered that grouping and sorting by LanguageCaption works just fine. It also started working fine after I renamed LanguageId to MyLanguageId. So where on earth is this documented that LanguageId appears to be a system variable / reserved word / keyword of some sort in SQL Server Reporting Services that must be avoided at all costs?? I can't seem to find anything on that topic - even Mr. Google and Mrs. Bing came up empty so far....

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  • Reversing a circular deque without a sentinel

    - by SDLFunTimes
    Hey Stackoverflow I'm working on my homework and I'm trying to reverse a circular-linked deque without a sentinel. Here are my data structures: struct DLink { TYPE value; struct DLink * next; struct DLink * prev; }; struct cirListDeque { int size; struct DLink *back; }; Here's my approach to reversing the deque: void reverseCirListDeque(struct cirListDeque* q) { struct DLink* current; struct DLink* temp; temp = q->back->next; q->back->next = q->back->prev; q->back->prev = temp; current = q->back->next; while(current != q->back->next) { temp = current->next; current->next = current->prev; current->prev = temp; current = current->next; } } However when I run it and put values 1, 2 and 3 on it (TYPE is just a alias for int in this case) and reverse it I get 2, 3, null. Does anyone have any ideas as to what I may be doing wrong? Thanks in advance.

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  • floating point equality in Python and in general

    - by eric.frederich
    I have a piece of code that behaves differently depending on whether I go through a dictionary to get conversion factors or whether I use them directly. The following piece of code will print 1.0 == 1.0 -> False But if you replace factors[units_from] with 10.0 and factors[units_to ] with 1.0 / 2.54 it will print 1.0 == 1.0 -> True #!/usr/bin/env python base = 'cm' factors = { 'cm' : 1.0, 'mm' : 10.0, 'm' : 0.01, 'km' : 1.0e-5, 'in' : 1.0 / 2.54, 'ft' : 1.0 / 2.54 / 12.0, 'yd' : 1.0 / 2.54 / 12.0 / 3.0, 'mile' : 1.0 / 2.54 / 12.0 / 5280, 'lightyear' : 1.0 / 2.54 / 12.0 / 5280 / 5.87849981e12, } # convert 25.4 mm to inches val = 25.4 units_from = 'mm' units_to = 'in' base_value = val / factors[units_from] ret = base_value * factors[units_to ] print ret, '==', 1.0, '->', ret == 1.0 Let me first say that I am pretty sure what is going on here. I have seen it before in C, just never in Python but since Python in implemented in C we're seeing it. I know that floating point numbers will change values going from a CPU register to cache and back. I know that comparing what should be two equal variables will return false if one of them was paged out while the other stayed resident in a register. Questions What is the best way to avoid problems like this?... In Python or in general. Am I doing something completely wrong? Side Note This is obviously part of a stripped down example but what I'm trying to do is come with with classes of length, volume, etc that can compare against other objects of the same class but with different units. Rhetorical Questions If this is a potentially dangerous problem since it makes programs behave in an undetermanistic matter, should compilers warn or error when they detect that you're checking equality of floats Should compilers support an option to replace all float equality checks with a 'close enough' function? Do compilers already do this and I just can't find the information.

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  • Altering an embedded truetype font so it will be useable by Windows GDI

    - by Ritsaert Hornstra
    I am trying to render PDF content to a GDI device context (a 24bit bitmap to be exact). Parsing the PDF stream into PDF objects and rendering the PDF commands from the content dictionary works well, inclduing font rendering. Embedded fonts are decompressed from their FontFile streams and "loaded" using AddFontMemResourceEx. Now some embedded fonts remove some TrueType tables that are needed by GDI, like the NAME table. Because of this, I tried to modify the font by parsing the TrueType subset font into it's tables and modify those tables that have data missing / missing tables are regenerated with as correct information as possible. I use the Microsoft Font Validator tool to see how "correct" the generated font is. I still get a few errors, like for the maxp table the max values are usually too large (it is a subset) or The xAvgCharWidth field does not equal the calculated value of the OS/2 table is not correct but this does not stop other embedded fonts to be useable.The fonts embedded using PDFCreator are the ones that are problematic. Question: - How can I determine what I need to change to the font file in order for GDI to be able to use it? - Are there any other font validation tools that might give me insight into what is still wrong with the fontfile? If needed: I can make an original fontfile and an altered fontfile available for download somewhere.

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  • Audio output from Silverlight

    - by leecarter
    I'm looking to develop a Silverlight application which will take a stream of data (not an audio stream as such) from a web server. The data stream would then be manipulated to give audio of a certain format (G.711 a-Law for example) which would then be converted into PCM so that additional effects can be applied (such as boosting the volume). I'm OK up to this point. I've got my data, converted the G.711 into PCM but my problem is being able to output this PCM audio to the sound card. I basing a solution on some C# code intended for a .Net application but in Silverlight there is a problem with trying to take a copy of a delegate (function pointer) which will be the topic of a separate question once I've produced a simple code sample. So, the question is... How can I output the PCM audio that I have held in a data structure (currently an array) in my Silverlight to the user? (Please don't say write the byte values to a text box) If it were a MP3 or WMA file I would play it using a MediaElement but I don't want to have to make it into a file as this would put a crimp on applying dynamic effects to the audio. I've seen a few posts from people saying low level audio support is poor/non-existant in Silverlight so I'm open to any suggestions/ideas people may have.

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  • sql statement supposed to have 2 distinct rows, but only 1 is returned

    - by jello
    I have an sql statement that is supposed to return 2 rows. the first with psychological_id = 1, and the second, psychological_id = 2. here is the sql statement select * from psychological where patient_id = 12 and symptom = 'delire'; But with this code, with which I populate an array list with what is supposed to be 2 different rows, two rows exist, but with the same values: the second row. OneSymptomClass oneSymp = new OneSymptomClass(); ArrayList oneSympAll = new ArrayList(); string connStrArrayList = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\PatientMonitoringDatabase.mdf; " + "Initial Catalog=PatientMonitoringDatabase; " + "Integrated Security=True"; string queryStrArrayList = "select * from psychological where patient_id = " + patientID.patient_id + " and symptom = '" + SymptomComboBoxes[tag].SelectedItem + "';"; using (var conn = new SqlConnection(connStrArrayList)) using (var cmd = new SqlCommand(queryStrArrayList, conn)) { conn.Open(); using (SqlDataReader rdr = cmd.ExecuteReader()) { while (rdr.Read()) { oneSymp.psychological_id = Convert.ToInt32(rdr["psychological_id"]); oneSymp.patient_history_date_psy = (DateTime)rdr["patient_history_date_psy"]; oneSymp.strength = Convert.ToInt32(rdr["strength"]); oneSymp.psy_start_date = (DateTime)rdr["psy_start_date"]; oneSymp.psy_end_date = (DateTime)rdr["psy_end_date"]; oneSympAll.Add(oneSymp); } } conn.Close(); } OneSymptomClass testSymp = oneSympAll[0] as OneSymptomClass; MessageBox.Show(testSymp.psychological_id.ToString()); the message box outputs "2", while it's supposed to output "1". anyone got an idea what's going on?

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  • Is there really such a thing as a char or short in modern programming?

    - by Dean P
    Howdy all, I've been learning to program for a Mac over the past few months (I have experience in other languages). Obviously that has meant learning the Objective C language and thus the plainer C it is predicated on. So I have stumbles on this quote, which refers to the C/C++ language in general, not just the Mac platform. With C and C++ prefer use of int over char and short. The main reason behind this is that C and C++ perform arithmetic operations and parameter passing at integer level, If you have an integer value that can fit in a byte, you should still consider using an int to hold the number. If you use a char, the compiler will first convert the values into integer, perform the operations and then convert back the result to char. So my question, is this the case in the Mac Desktop and IPhone OS environments? I understand when talking about theses environments we're actually talking about 3-4 different architectures (PPC, i386, Arm and the A4 Arm variant) so there may not be a single answer. Nevertheless does the general principle hold that in modern 32 bit / 64 bit systems using 1-2 byte variables that don't align with the machine's natural 4 byte words doesn't provide much of the efficiency we may expect. For instance, a plain old C-Array of 100,000 chars is smaller than the same 100,000 ints by a factor of four, but if during an enumeration, reading out each index involves a cast/boxing/unboxing of sorts, will we see overall lower 'performance' despite the saved memory overhead?

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  • Tree data in MySql database table

    - by Robert Koritnik
    I have a table that uses Adjacency list model for hierarchy storage. My most relevant columns in this table are therefore: ItemId // is auto_increment ParentId Level ParentTrail // in the form of "parentId/../parentId/itemId" then I created a before insert tigger, that populates columns Level and ParentTrail. Since the last column also includes current item's ID I had to use a trick in my trigger because auto_increment columns are not available in the before insert trigger. So I get that value from the information_schema.tables table. All works fine, until I try to write an update trigger, that would update my item and its descendants when the item changes its parent (ParentId has changed). But I can't make an update on my table inside the update trigger. All I can do is to change current record's values but not other's. I could use a separate table for hierarchy data, but that would mean that I would also have to create a view that would combine these two tables (1:1 relation) and I would like to avoid this is at all possible. Is there a way to have all these in the same table so that these fields (Level and ParetTrail) set/update themselves automagically using triggers?

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  • problem with insert into mysql DB using PHP

    - by user504363
    Hi all I have strange problem that I have a PHP page used to insert data into Mysql DB. the problem is that when I execute the code, nothing added to db and no errors is appeared although I set display errors codes error_reporting(E_ALL); ini_set('display_errors', TRUE); ini_set('display_startup_errors', TRUE); any idea about this problem ! here is my used code for inserting function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") { if (PHP_VERSION < 6) { $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue; } $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue); switch ($theType) { case "text": $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL"; break; case "long": case "int": $theValue = ($theValue != "") ? intval($theValue) : "NULL"; break; case "double": $theValue = ($theValue != "") ? doubleval($theValue) : "NULL"; break; case "date": $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL"; break; case "defined": $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue; break; } return $theValue; } include("Connections/mzk_mdc.php"); $ext = 1; $website = "mzk"; $mzk_sql=sprintf("INSERT INTO downloads (image, `by`, `rapid_title`, title, `description`, category, div_id, topic_url, down_times, ext, `website`) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)", GetSQLValueString($topic_thumb_image, "text"), GetSQLValueString($topic_by, "text"), GetSQLValueString($topic_des, "text"), GetSQLValueString($topic_title, "text"), GetSQLValueString($forum_content, "text"), GetSQLValueString($topic_category, "text"),GetSQLValueString($topic_div, "text"),GetSQLValueString($forum_link, "text") ,GetSQLValueString($topic_down_times, "int"),GetSQLValueString($ext, "int"), GetSQLValueString($website, "text")); mysql_select_db($database_mdc, $mdc); $mzk_result = mysql_query($mzk_sql, $mdc) or die("can not do more"); mysql_close($mdc);

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