Search Results

Search found 355 results on 15 pages for 'tuple'.

Page 13/15 | < Previous Page | 9 10 11 12 13 14 15  | Next Page >

  • How to enforce foreign keys using Xerial SQLite JDBC?

    - by Space_C0wb0y
    According to their release notes, the Xerial SQLite JDBC driver supports foreign keys since version 3.6.20.1. I have tried some time now to get a foreign key constraint to be enforced, but to no avail. Here is what I came up with: public static void main(String[] args) throws ClassNotFoundException, SQLException { Class.forName("org.sqlite.JDBC"); SQLiteConfig config = new SQLiteConfig(); config.enforceForeignKeys(true); Connection connection = DriverManager.getConnection("jdbc:sqlite::memory:", config.toProperties()); connection.createStatement().executeUpdate( "CREATE TABLE artist(" + "artistid INTEGER PRIMARY KEY, " + "artistname TEXT);"); connection.createStatement().executeUpdate( "CREATE TABLE track("+ "trackid INTEGER," + "trackname TEXT," + "trackartist INTEGER," + "FOREIGN KEY(trackartist) REFERENCES artist(artistid)" + ");"); connection.createStatement().executeUpdate( "INSERT INTO track VALUES(14, 'Mr. Bojangles', 3)"); } The table definitions are taken directly from the sample in the SQLite documentation. This is supposed to fail, but it doesn't. I also checked, and it really inserts the tuple (no ignore or something like that). Does anyone have any experience with that, or knows how to make it work?

    Read the article

  • More FP-correct way to create an update sql query

    - by James Black
    I am working on access a database using F# and my initial attempt at creating a function to create the update query is flawed. let BuildUserUpdateQuery (oldUser:UserType) (newUser:UserType) = let buf = new System.Text.StringBuilder("UPDATE users SET "); if (oldUser.FirstName.Equals(newUser.FirstName) = false) then buf.Append("SET first_name='").Append(newUser.FirstName).Append("'" ) |> ignore if (oldUser.LastName.Equals(newUser.LastName) = false) then buf.Append("SET last_name='").Append(newUser.LastName).Append("'" ) |> ignore if (oldUser.UserName.Equals(newUser.UserName) = false) then buf.Append("SET username='").Append(newUser.UserName).Append("'" ) |> ignore buf.Append(" WHERE id=").Append(newUser.Id).ToString() This doesn't properly put a , between any update parts after the first, for example: UPDATE users SET first_name='Firstname', last_name='lastname' WHERE id=... I could put in a mutable variable to keep track when the first part of the set clause is appended, but that seems wrong. I could just create an list of tuples, where each tuple is oldtext, newtext, columnname, so that I could then loop through the list and build up the query, but it seems that I should be passing in a StringBuilder to a recursive function, returning back a boolean which is then passed as a parameter to the recursive function. Does this seem to be the best approach, or is there a better one?

    Read the article

  • help('modules') crashing?

    - by Chris
    I was trying to install a module for opencv and added an opencv.pth file to the folder beyond my sites.py file. I have since deleted it and no change. When I try to run help('modules'), I get the following error: Please wait a moment while I gather a list of all available modules... /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/twisted/words/im/init.py:8: UserWarning: twisted.im will be undergoing a rewrite at some point in the future. warnings.warn("twisted.im will be undergoing a rewrite at some point in the future.") /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py:110: DeprecationWarning: The wxPython compatibility package is no longer automatically generated or actively maintained. Please switch to the wx package as soon as possible. import(name) Traceback (most recent call last): File "", line 1, in File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site.py", line 348, in call return pydoc.help(*args, **kwds) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1644, in call self.help(request) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1681, in help elif request == 'modules': self.listmodules() File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1802, in listmodules ModuleScanner().run(callback) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1853, in run for importer, modname, ispkg in pkgutil.walk_packages(): File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py", line 110, in walk_packages import(name) File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/init.py", line 19, in from ctypes_opencv.cv import * File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/cv.py", line 2567, in ('desc', CvMat_r, 1), # CvMat* desc File "/Library/Python/2.5/site-packages/ctypes_opencv/cxcore.py", line 114, in cfunc return CFUNCTYPE(result, *atypes)((name, dll), tuple(aflags)) AttributeError: dlsym(0x2674d10, cvCreateFeatureTree): symbol not found What gives?!

    Read the article

  • How to convert from hex-encoded string to a "human readable" string?

    - by John Jensen
    I'm using the Net-SNMP bindings for python and I'm attempting to grab an ARP cache from a Brocade switch. Here's what my code looks like: #!/usr/bin/env python import netsnmp def get_arp(): oid = netsnmp.VarList(netsnmp.Varbind('ipNetToMediaPhysAddress')) res = netsnmp.snmpwalk(oid, Version=2, DestHost='10.0.1.243', Community='public') return res arp_table = get_arp() print arp_table The SNMP code itself is working fine. Output from snmpwalk looks like this: <snip> IP-MIB::ipNetToMediaPhysAddress.128.10.200.6.158 = STRING: 0:1b:ed:a3:ec:c1 IP-MIB::ipNetToMediaPhysAddress.129.10.200.6.162 = STRING: 0:1b:ed:a4:ac:c1 IP-MIB::ipNetToMediaPhysAddress.130.10.200.6.166 = STRING: 0:1b:ed:38:24:1 IP-MIB::ipNetToMediaPhysAddress.131.10.200.6.170 = STRING: 74:8e:f8:62:84:1 </snip> But my output from the python script yields a tuple of hex-encoded strings that looks like this: ('\x00$8C\x98\xc1', '\x00\x1b\xed;_A', '\x00\x1b\xed\xb4\x8f\x81', '\x00$86\x15\x81', '\x00$8C\x98\x81', '\x00\x1b\xed\x9f\xadA', ...etc) I've spent some time googling and came across the struct module and the .decode("hex") string method, but the .decode("hex") method doesn't seem to work: Python 2.7.3 (default, Apr 10 2013, 06:20:15) [GCC 4.6.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> hexstring = '\x00$8C\x98\xc1' >>> newstring = hexstring.decode("hex") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib/python2.7/encodings/hex_codec.py", line 42, in hex_decode output = binascii.a2b_hex(input) TypeError: Non-hexadecimal digit found >>> And the documentation for struct is a bit over my head.

    Read the article

  • How to Use XSLT to Replace Coordinate Separator With List of Tuples?

    - by kuloch
    I have a space-separated list of coordinate tuples. Each tuple consists of a space-separated list of 2-dimensional coordinates. E.g. "1.1 2.8 1.2 2.9" represents a line from POINT(1.1 2.8) to POINT(1.2 2.9). I need this to instead be "1.1,2.8 1.2,2.9". How would I use XSLT to perform the replacement of space-to-comma between pairs of numbers? I have the "string(gml:LinearRing/gml:posList)". This is being used on a Java Web Service that spits out GML 3.1.1 features with geometries. The service supports optional KML output, by using XSLT to transform the GML document into a KML document (at least, the chunks deemed "important"). I am locked into XSLT 1.0, so regex from XSLT 2.0 is not an option. I am aware that GML uses lat/lon while KML uses lon/lat. That's being handled before XSLT, though it would be nice to have that also done with XSLT.

    Read the article

  • Python and Unicode: How everything should be Unicode

    - by A A
    Forgive if this a long a question: I have been programming in Python for around six months. Self taught, starting with the Python tutorial and then SO and then just using Google for stuff. Here is the sad part: No one told me all strings should be Unicode. No, I am not lying or making this up, but where does the tutorial mention it? And most examples also I see just make use of byte strings, instead of Unicode strings. I was just browsing and came across this question on SO, which says how every string in Python should be a Unicode string. This pretty much made me cry! I read that every string in Python 3.0 is Unicode by default, so my questions are for 2.x: Should I do a: print u'Some text' or just print 'Text' ? Everything should be Unicode, does this mean, like say I have a tuple: t = ('First', 'Second'), it should be t = (u'First', u'Second')? I read that I can do a from __future__ import unicode_literals and then every string will be a Unicode string, but should I do this inside a container also? When reading/ writing to a file, I should use the codecs module. Right? Or should I just use the standard way or reading/ writing and encode or decode where required? If I get the string from say raw_input(), should I convert that to Unicode also? What is the common approach to handling all of the above issues in 2.x? The from __future__ import unicode_literals statement? Sorry for being a such a noob, but this changes what I have been doing for a long time and so clearly I am confused.

    Read the article

  • Practiaal rules for Django MiddleWare ordering?

    - by o_O Tync
    The official documentation is a bit messy: 'before' & 'after' are used for ordering MiddleWare in a tuple, but in some places 'before'&'after' refers to request-response phases. Also, 'should be first/last' are mixed and it's not clear which one to use as 'first'. I do understand the difference.. however it seems to complicated for a newbie in Django. Can you suggest some correct ordering for builtin MiddleWare classes (assuming we enable all of them) and — most importantly — explain WHY one goes before/after other ones? here's the list, with the info from docs I managed to find: UpdateCacheMiddleware Before those that modify 'Vary:' SessionMiddleware, GZipMiddleware, LocaleMiddleware GZipMiddleware Before any MW that may change or use the response body After UpdateCacheMiddleware: Modifies 'Vary:' ConditionalGetMiddleware Before CommonMiddleware: uses its 'Etag:' header when USE_ETAGS=True SessionMiddleware After UpdateCacheMiddleware: Modifies 'Vary:' Before TransactionMiddleware: we don't need transactions here LocaleMiddleware, One of the topmost, after SessionMiddleware, CacheMiddleware After UpdateCacheMiddleware: Modifies 'Vary:' After SessionMiddleware: uses session data CommonMiddleware Before any MW that may change the response (it calculates ETags) After GZipMiddleware so it won't calculate an E-Tag on gzipped contents Close to the top: it redirects when APPEND_SLASH or PREPEND_WWW CsrfViewMiddleware AuthenticationMiddleware After SessionMiddleware: uses session storage MessageMiddleware After SessionMiddleware: can use Session-based storage XViewMiddleware TransactionMiddleware After MWs that use DB: SessionMiddleware (configurable to use DB) All *CacheMiddleWare is not affected (as an exception: uses own DB cursor) FetchFromCacheMiddleware After those those that modify 'Vary:' if uses them to pick a value for cache hash-key After AuthenticationMiddleware so it's possible to use CACHE_MIDDLEWARE_ANONYMOUS_ONLY FlatpageFallbackMiddleware Bottom: last resort Uses DB, however, is not a problem for TransactionMiddleware (yes?) RedirectFallbackMiddleware Bottom: last resort Uses DB, however, is not a problem for TransactionMiddleware (yes?) (I will add suggestions to this list to collect all of them in one place)

    Read the article

  • C# Tupel group limitation

    - by user609511
    How can i controll the loop of Tupel Repeatation ? Someone has give me a hint about my algorithm. I modified a little bit his algorithm. int LimCol = Convert.ToInt32(LimitColis); result = oListTUP .GroupBy(x => x.Item1) .Select(g => new { Key = g.Key, Sum = g.Sum(x => x.Item2), Poids = g.Sum(x => x.Item3), }) .Select(p => new { Key = p.Key, Items = Enumerable.Repeat(LimCol , p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, 1)), CalculPoids = p.Poids / (Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, 1))).Count() }) .SelectMany(p => p.Items.Select(i => Tuple.Create(p.Key, i, p.CalculPoids))) .ToList(); foreach (var oItem in result) { Label1.Text += oItem.Item1 + "--" + oItem.Item2 + "--" + oItem.Item3 + "<br>"; } the result with LimCol = 3 as you can see i colored with red is the problem. i expected: 0452632--3--3,75 0452632--3--3,75 0452632--3--3,75 0452632--3--3,75 essai 49--3--79,00 essai 49--2--79,00 Thanks you in advance

    Read the article

  • Dynamically setting the queryset of a ModelMultipleChoiceField to a custom recordset

    - by Daniel Quinn
    I've seen all the howtos about how you can set a ModelMultipleChoiceField to use a custom queryset and I've tried them and they work. However, they all use the same paradigm: the queryset is just a filtered list of the same objects. In my case, I'm trying to get the admin to draw a multiselect form that instead of using usernames as the text portion of the , I'd like to use the name field from my account class. Here's a breakdown of what I've got: # models.py class Account(models.Model): name = models.CharField(max_length=128,help_text="A display name that people understand") user = models.ForeignKey(User, unique=True) # Tied to the User class in settings.py class Organisation(models.Model): administrators = models.ManyToManyField(User) # admin.py from django.forms import ModelMultipleChoiceField from django.contrib.auth.models import User class OrganisationAdminForm(forms.ModelForm): def __init__(self, *args, **kwargs): from ethico.accounts.models import Account self.base_fields["administrators"] = ModelMultipleChoiceField( queryset=User.objects.all(), required=False ) super(OrganisationAdminForm, self).__init__(*args, **kwargs) class Meta: model = Organisation This works, however, I want queryset above to draw a selectbox with the Account.name property and the User.id property. This didn't work: queryset=Account.objects.all().order_by("name").values_list("user","name") It failed with this error: 'tuple' object has no attribute 'pk' I figured that this would be easy, but it's turned into hours of dead-ends. Anyone care to shed some light?

    Read the article

  • What is the corrrect way to increment a field making up part of a composit key

    - by Tr1stan
    I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

    Read the article

  • Spawning a thread in python

    - by morpheous
    I have a series of 'tasks' that I would like to run in separate threads. The tasks are to be performed by separate modules. Each containing the business logic for processing their tasks. Given a tuple of tasks, I would like to be able to spawn a new thread for each module as follows. from foobar import alice, bob charles data = getWorkData() # these are enums (which I just found Python doesn't support natively) :( tasks = (alice, bob, charles) for task in tasks # Ok, just found out Python doesn't have a switch - @#$%! # yet another thing I'll need help with then ... switch case alice: #spawn thread here - how ? alice.spawnWorker(data) No prizes for guessing I am still thinking in C++. How can I write this in a Pythonic way using Pythonic 'enums' and 'switch'es, and be able to run a module in a new thread. Obviously, the modules will all have a class that is derived from a ABC (abstract base class) called Plugin. The spawnWorker() method will be declared on the Plugin interface and defined in the classes implemented in the various modules. Maybe, there is a better (i.e. Pythonic) way of doing all this?. I'd be interested in knowing

    Read the article

  • F# Higher-order property accessors

    - by Nathan Sanders
    I just upgraded my prototyping tuple to a record. Someday it may become a real class. In the meantime, I want to translate code like this: type Example = int * int let examples = [(1,2); (3,4); (5,6)] let field1s = Seq.map (fst >> printfn "%d") examples to this: type Example = { Field1 : int Field2 : int Description : string } let examples = [{Field1 = 1; Field2 = 2; Description = "foo"} {Field1 = 3; Field2 = 4; Description = "bar"} {Field1 = 5; Field2 = 6; Description = "baz"}] let field1s = Seq.map Description examples The problem is that I expected to get a function Description : Example -> string when I declared the Example record, but I don't. I've poked around a little and tried properties on classes, but that doesn't work either. Am I just missing something in the documentation or will I have to write higher-order accessors manually? (That's the workaround I'm using now.)

    Read the article

  • I don't like Python functions that take two or more iterables. Is it a good idea?

    - by Xavier Ho
    This question came from looking at this question on Stackoverflow. def fringe8((px, py), (x1, y1, x2, y2)): Personally, it's been one of my pet peeves to see a function that takes two arguments with fixed-number iterables (like a tuple) or two or more dictionaries (Like in the Shotgun API). It's just hard to use, because of all the verbosity and double-bracketed enclosures. Wouldn't this be better: >>> class Point(object): ... def __init__(self, x, y): ... self.x = x ... self.y = y ... >>> class Rect(object): ... def __init__(self, x1, y1, x2, y2): ... self.x1 = x1 ... self.y1 = y1 ... self.x2 = x2 ... self.y2 = y2 ... >>> def fringe8(point, rect): ... # ... ... >>> >>> point = Point(2, 2) >>> rect = Rect(1, 1, 3, 3) >>> >>> fringe8(point, rect) Is there a situation where taking two or more iterable arguments is justified? Obviously the standard itertools Python library needs that, but I can't see it being pretty in maintainable, flexible code design.

    Read the article

  • SQLAlchemy Mapping problem

    - by asdvalkn
    Dear Everyone, I am trying to sqlalchemy to correctly map my data. Note that a unified group is basically a group of groups. (One unifiedGroup maps to many groups but each group can only map to one ug). So basically this is the definition of my unifiedGroups: CREATE TABLE `unifiedGroups` ( `ugID` INT AUTO_INCREMENT, `gID` INT NOT NULL, PRIMARY KEY(`ugID`, `gID`), KEY( `gID`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 ; Note that each row is a ugID, gID tuple. ( I do not know before hand how many gID is per ugID so this is probably the most sensible and simplest method). Definition for my UnifiedGroup class class UnifiedGroup(object): """UnifiedProduct behaves very much like a group """ def __init__(self, ugID): self.ugID=ugID #Added by mapping self.groups=False def __str__(self): return '<%s:%s>' % (self.ugID, ','.join( [g for g in self.groups])) These are my mapping tables: tb_groupsInfo = Table( 'groupsInfo', metadata, Column('gID', Integer, primary_key=True), Column('gName', String(128)), ) tb_unifiedGroups = Table( 'unifiedGroups', metadata, Column('ugID', Integer, primary_key=True), Column('gID', Integer, ForeignKey('groupsInfo.gID')), ) My mapper maps in the following manner: mapper( UnifiedGroup, tb_unifiedGroups, properties={ 'groups': relation( Group, backref='unifiedGroup') }) However, when I tried to do groupInstance.unifiedGroup, I am getting an empty list [], while groupInstance.unifiedGroup.groups returns me an error: AttributeError: 'InstrumentedList' object has no attribute 'groups' Traceback (most recent call last): File "Mapping.py", line 119, in <module> print p.group.unifiedGroup.groups AttributeError: 'InstrumentedList' object has no attribute 'groups' What is wrong?

    Read the article

  • Recursive templates: compilation error under g++

    - by Johannes
    Hi, I am trying to use templates recursively to define (at compile-time) a d-tuple of doubles. The code below compiles fine with Visual Studio 2010, but g++ fails and complains that it "cannot call constructor 'point<1::point' directly". Could anyone please shed some light on what is going on here? Many thanks, Jo #include <iostream> #include <utility> using namespace std; template <const int N> class point { private: pair<double, point<N-1> > coordPointPair; public: point() { coordPointPair.first = 0; coordPointPair.second.point<N-1>::point(); } }; template<> class point<1> { private: double coord; public: point() { coord= 0; } }; int main() { point<5> myPoint; return 0; }

    Read the article

  • Slightly different execution times between python2 and python3

    - by user557634
    Hi. Lastly I wrote a simple generator of permutations in python (implementation of "plain changes" algorithm described by Knuth in "The Art... 4"). I was curious about the differences in execution time of it between python2 and python3. Here is my function: def perms(s): s = tuple(s) N = len(s) if N <= 1: yield s[:] raise StopIteration() for x in perms(s[1:]): for i in range(0,N): yield x[:i] + (s[0],) + x[i:] I tested both using timeit module. My tests: $ echo "python2.6:" && ./testing.py && echo "python3:" && ./testing3.py python2.6: args time[ms] 1 0.003811 2 0.008268 3 0.015907 4 0.042646 5 0.166755 6 0.908796 7 6.117996 8 48.346996 9 433.928967 10 4379.904032 python3: args time[ms] 1 0.00246778964996 2 0.00656183719635 3 0.01419159912 4 0.0406293644678 5 0.165960511097 6 0.923101452814 7 6.24257639835 8 53.0099868774 9 454.540967941 10 4585.83498001 As you can see, for number of arguments less than 6, python 3 is faster, but then roles are reversed and python2.6 does better. As I am a novice in python programming, I wonder why is that so? Or maybe my script is more optimized for python2? Thank you in advance for kind answer :)

    Read the article

  • Using items in a list as arguments

    - by Travis Brown
    Suppose I have a function with the following type signature: g :: a -> a -> a -> b I also have a list of as—let's call it xs—that I know will contain at least three items. I'd like to apply g to the first three items of xs. I know I could define a combinator like the following: ($$$) :: (a -> a -> a -> b) -> [a] -> b f $$$ (x:y:z:_) = f x y z Then I could just use g $$$ xs. This makes $$$ a bit like uncurry, but for a function with three arguments of the same type and a list instead of a tuple. Is there a way to do this idiomatically using standard combinators? Or rather, what's the most idiomatic way to do this in Haskell? I thought trying pointfree on a non-infix version of $$$ might give me some idea of where to start, but the output was an abomination with 10 flips, a handful of heads and tails and aps, and 28 parentheses. (NB: I know this isn't a terribly Haskelly thing to do in the first place, but I've come across a couple of situations where it seems like a reasonable solution, especially when using Parsec. I'll certainly accept "don't ever do this in real code" if that's the best answer, but I'd prefer to see some clever trick involving the ((->) r) monad or whatever.)

    Read the article

  • Combining Java hashcodes into a "master" hashcode

    - by Nick Wiggill
    I have a vector class with hashCode() implemented. It wasn't written by me, but uses 2 prime numbers by which to multiply the 2 vector components before XORing them. Here it is: /*class Vector2f*/ ... public int hashCode() { return 997 * ((int)x) ^ 991 * ((int)y); //large primes! } ...As this is from an established Java library, I know that it works just fine. Then I have a Boundary class, which holds 2 vectors, "start" and "end" (representing the endpoints of a line). The values of these 2 vectors are what characterize the boundary. /*class Boundary*/ ... public int hashCode() { return 1013 * (start.hashCode()) ^ 1009 * (end.hashCode()); } Here I have attempted to create a good hashCode() for the unique 2-tuple of vectors (start & end) constituting this boundary. My question: Is this hashCode() implementation going to work? (Note that I have used 2 different prime numbers in the latter hashCode() implementation; I don't know if this is necessary but better to be safe than sorry when trying to avoid common factors, I guess -- since I presume this is why primes are popular for hashing functions.)

    Read the article

  • Writing functions of tuples conveniently in Scala

    - by Alexey Romanov
    Quite a few functions on Map take a function on a key-value tuple as the argument. E.g. def foreach(f: ((A, B)) ? Unit): Unit. So I looked for a short way to write an argument to foreach: > val map = Map(1 -> 2, 3 -> 4) map: scala.collection.immutable.Map[Int,Int] = Map(1 -> 2, 3 -> 4) > map.foreach((k, v) => println(k)) error: wrong number of parameters; expected = 1 map.foreach((k, v) => println(k)) ^ > map.foreach({(k, v) => println(k)}) error: wrong number of parameters; expected = 1 map.foreach({(k, v) => println(k)}) ^ > map.foreach(case (k, v) => println(k)) error: illegal start of simple expression map.foreach(case (k, v) => println(k)) ^ I can do > map.foreach(_ match {case (k, v) => println(k)}) 1 3 Any better alternatives?

    Read the article

  • LINQ to SQL Converter

    - by user609511
    How can I convert My LINQ to SQL ? i have this LINQ statement: int LimCol = Convert.ToInt32(LimitColis); result = oListTUP .GroupBy(x => new { x.Item1, x.Item2, x.Item3, x.Item4, x.Item5 }) .Select(g => new { Key = g.Key, Sum = g.Sum(x => x.Item6), Poids = g.Sum(x => x.Item7), }) .Select(p => new { Key = p.Key, Items = Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, p.Sum % LimCol > 0 ? 1 : 0)), CalculPoids = p.Poids / Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, p.Sum % LimCol > 0 ? 1 : 0)).Count() }) .SelectMany(p => p.Items.Select(i => Tuple.Create(p.Key.Item1, p.Key.Item2, p.Key.Item3, p.Key.Item4, p.Key.Item5, i, p.CalculPoids))) .ToList(); } It works well, but somehow want to push it and it become too complicated, so I want to convert it into Pure SQL. I have tried SQL Profiler and LinqPad, but neither shows me the SQL. How can I see the SQL code from My LINQ ? Thank you in advance.

    Read the article

  • How do I set up the python/c library correctly?

    - by Bartvbl
    I have been trying to get the python/c library to like my mingW compiler. The python online doncumentation; http://docs.python.org/c-api/intro.html#include-files only mentions that I need to import the python.h file. I grabbed it from the installation directory (as is required on the windows platform), and tested it by compiling the script: #include "Python.h". This compiled fine. Next, I tried out the snippet of code shown a bit lower on the python/c API page: PyObject *t; t = PyTuple_New(3); PyTuple_SetItem(t, 0, PyInt_FromLong(1L)); PyTuple_SetItem(t, 1, PyInt_FromLong(2L)); PyTuple_SetItem(t, 2, PyString_FromString("three")); For some reason, the compiler would compile the code if I'd remove the last 4 lines (so that only the pyObject variable definition would be left), yet calling the actual constructor of the tuple returned errors. I am probably missing something completely obvious here, given I am very new to C, but does anyone know what it is?

    Read the article

  • help('modules') crashing? Not sure how to fix..

    - by Chris
    I was trying to install a module for opencv and added an opencv.pth file to the folder beyond my sites.py file. I have since deleted it and no change. When I try to run help('modules'), I get the following error: Please wait a moment while I gather a list of all available modules... /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/twisted/words/im/init.py:8: UserWarning: twisted.im will be undergoing a rewrite at some point in the future. warnings.warn("twisted.im will be undergoing a rewrite at some point in the future.") /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py:110: DeprecationWarning: The wxPython compatibility package is no longer automatically generated or actively maintained. Please switch to the wx package as soon as possible. import(name) Traceback (most recent call last): File "", line 1, in File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site.py", line 348, in call return pydoc.help(*args, **kwds) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1644, in call self.help(request) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1681, in help elif request == 'modules': self.listmodules() File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1802, in listmodules ModuleScanner().run(callback) File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pydoc.py", line 1853, in run for importer, modname, ispkg in pkgutil.walk_packages(): File "/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/pkgutil.py", line 110, in walk_packages import(name) File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/init.py", line 19, in from ctypes_opencv.cv import * File "/BinaryCache/wxWidgets/wxWidgets-11~262/Root/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/wxaddons/init.py", line 180, in import_hook File "/Library/Python/2.5/site-packages/ctypes_opencv/cv.py", line 2567, in ('desc', CvMat_r, 1), # CvMat* desc File "/Library/Python/2.5/site-packages/ctypes_opencv/cxcore.py", line 114, in cfunc return CFUNCTYPE(result, *atypes)((name, dll), tuple(aflags)) AttributeError: dlsym(0x2674d10, cvCreateFeatureTree): symbol not found What gives?!

    Read the article

  • MySQLDB query not returning all rows

    - by RBK
    I am trying to do a simple fetch using MySQLDB in Python. I have 2 tables(Accounts & Products). I have to look up Accounts table, get acc_id from it & query the Products table using it. The Products tables has more than 10 rows. But when I run this code it randomly returns between 0 & 6 rows each time I run it. Here's the code snippet: # Set up connection con = mdb.connect('db.xxxxx.com', 'user', 'password', 'mydb') # Create cursor cur = con.cursor() # Execute query cur.execute("SELECT acc_id FROM Accounts WHERE ext_acc = '%s'" % account_num ) # account_num is alpha-numberic and is got from preceding part of the program # A tuple is returned, so get the 0th item from it acc_id = cur.fetchone()[0] print "account_id = ", acc_id # Close the cursor - I was not sure if I can reuse it cur.close() # Reopen the cursor cur = con.cursor() # Second query cur.execute("SELECT * FROM Products WHERE account_id = %d" % acc_id) keys = cur.fetchall() print cur.rowcount # This prints incorrect row count for key in keys: # Does not print all rows. Tried to directly print keys instead of iterating - same result :( print key # Closing the cursor & connection cur.close() con.close() The weird part is, I tried to step through the code using a debugger(PyDev on Eclipse) and it correctly gets all rows(both the value stored in the variable 'keys' as well as console output are correct). I am sure my DB has correct data since I ran the same SQL on MySQL console & got the correct result. Just to be sure I was not improperly closing the connection, I tried using with con instead of manually closing the connection and it's the same result. I did RTFM but I couldn't find much in it to help me with this issue. Where am I going wrong? Thank you. EDIT: I noticed another weird thing now. In the line cur.execute("SELECT * FROM Products WHERE account_id = %d" % acc_id), I hard-coded the acc_id value, i.e made it cur.execute("SELECT * FROM Products WHERE account_id = %d" % 322) and it returns all rows

    Read the article

  • Testing variable types in Python

    - by Jasper
    Hello, I'm creating an initialising function for the class 'Room', and found that the program wouldn't accept the tests I was doing on the input variables. Why is this? def __init__(self, code, name, type, size, description, objects, exits): self.code = code self.name = name self.type = type self.size = size self.description = description self.objects = objects self.exits = exits #Check for input errors: if type(self.code) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 110' elif type(self.name) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 111' elif type(self.type) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 112' elif type(self.size) != type(int()): print 'Error found in module rooms.py!' print 'Error number: 113' elif type(self.description) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 114' elif type(self.objects) != type(list()): print 'Error found in module rooms.py!' print 'Error number: 115' elif type(self.exits) != type(tuple()): print 'Error found in module rooms.py!' print 'Error number: 116' When I run this I get this error: Traceback (most recent call last): File "/Users/Jasper/Development/Programming/MyProjects/Game Making Challenge/Europa I/rooms.py", line 148, in <module> myRoom = Room(101, 'myRoom', 'Basic Room', 5, '<insert description>', myObjects, myExits) File "/Users/Jasper/Development/Programming/MyProjects/Game Making Challenge/Europa I/rooms.py", line 29, in __init__ if type(self.code) != type(str()): TypeError: 'str' object is not callable

    Read the article

  • Python: How to transfer varrying length arrays over a network connection

    - by Devin
    Hi, I need to transfer an array of varying length in which each element is a tuple of two integers. As an example: path = [(1,1),(1,2)] path = [(1,1),(1,2),(2,2)] I am trying to use pack and unpack, however, since the array is of varying length I don't know how to create a format such that both know the format. I was trying to turn it into a single string with delimiters, such as: msg = 1&1~1&2~ sendMsg = pack("s",msg) or sendMsg = pack("s",str(msg)) on the receiving side: path = unpack("s",msg) but that just prints 1 in this case. I was also trying to send 4 integers as well, which send and receive fine, so long as I don't include the extra string representing the path. sendMsg = pack("hhhh",p.direction[0],p.direction[1],p.id,p.health) on the receive side: x,y,id,health = unpack("hhhh",msg) The first was for illustration as I was trying to send the format "hhhhs", but either way the path doesn't come through properly. Thank-you for your help. I will also be looking at sending a 2D array of ints, but I can't seem to figure out how to send these more 'complex' structures across the network. Thank-you for your help.

    Read the article

< Previous Page | 9 10 11 12 13 14 15  | Next Page >