How expensive are local variables (var v), global variables (window.v) and cross-global variables (parent.v) in JavaScript, in the major browsers? Has anyone performed any good tests on this one?
Hi,
If I defined a ENUM in a base object with serveral default values. When I inherit from the base object I want to add more options the the ENUM list which are specific to the inheriting object.
For example my base could have a ENUM called Direction with values:
None
ALL
Stop
Start
I create a new class call Compass which inherits the base class and what to add the following to the ENUM Direction.
North
South
East
West
I create a new class call Navigation which inherits the base class and what to add the following to the ENUM Direction.
Left
Right
So, In my inheriting class haow do I extend the ENUM.
I am using VB.NET.
Regards
I have an array:
letterFrequency = [["a", 12], ["b", 25], ["c", 34], ["d", 1], ["e", 35], ["f", 8], ["g", 7], ["h", 67], ["i", 35], ["j", 0], ["k", 53], ["l", 0], ["m", 0], ["n", 3], ["o", 0], ["p", 0], ["q", 3], ["r", 153], ["s", 0], ["t", 0], ["u", 15], ["v", 0], ["w", 0], ["x", 3], ["y", 0], ["z", 0]]
and I want to sort it in descending order based on the number within the nested array i.e. letterFrequency[i][1]. So I want the most popular letter to be first. How would I do this?
I am in the process of setting up a batch script to do a specified action if the script was run on a weekday, and an alternate action if run on the weekend.
I am almost completely unfamiliar with writing batch scripts, but I know how to write my entire script except the logic I describe above. Can someone please answer both if it is possible, and if it is at least a framework of how to implement it. Thanks in advance.
So I've been set a task to create a temperature converter in C++ using this equation:
Celsius = (5/9)*(Fahrenheit – 32)
and so far I've come up with this (I've cut out the 10 lines worth of comments from the start so the code posted begins on line 11, if that makes any sense)
#include <iostream>
#include <string>
#include <iomanip>
#include <cmath>
using namespace std;
int main ()
{
float celsius;
float farenheit;
std::cout << "**************************" << endl;
std::cout << "*4001COMP-Lab5-Question 1*" << endl;
std::cout << "**************************" << endl << endl;
std::cout << "Please enter a temperature in farenheit: ";
std::cin >> farenheit >> endl;
std::cout << "Temperature (farenheit): " << endl;
std::cout << "Temperature (celsius): " << celsius << endl;
std::cin.get();
return 0;
}
Everytime I try to run this program I get a heap of errors with this one appearing every time:
1m:\visual studio 2010\projects\week 5\week 5\main.cpp(26): error C2678: binary '' : no operator found which takes a left-hand operand of type 'std::basic_istream<_Elem,_Traits' (or there is no acceptable conversion)
I've tried everything I can think of to get rid of this error but it reappears every time, any idea on how to fix this?
Both lines of code:
KeyPairGenerator.getInstance("RSA")
KeyPairGenerator.getInstance("RSA", "BC")
works well. So, what's the differecente using BC or not? Is BC completely compatible with the default RSA used? (using sun JDK 6)
I'm looking to implement a few nicer ways to use List in a couple of apps I'm working on. My current implementation looks like this.
MyPage.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
BLL.PostCollection oPost = new BLL.PostCollection();
oPost.OpenRecent();
rptPosts.DataSource = oArt;
rptPosts.DataBind();
}
BLL Class(s)
public class Post
{
public int PostId { get; set; }
public string PostTitle { get; set; }
public string PostContent { get; set; }
public string PostCreatedDate { get; set; }
public void OpenRecentInitFromRow(DataRow row)
{
this.PostId = (int) row["id"];
this.PostTitle = (string) row["title"];
this.PostContent = (string) row["content"];
this.PostCreatedDate = (DateTime) row["createddate"];
}
}
public class PostCollection : List<Post>
{
public void OpenRecent()
{
DataSet ds = DbProvider.Instance().Post_ListRecent();
foreach (DataRow row in ds.Tables[0].Rows)
{
Post oPost = new Post();
oPost.OpenRecentInitFromRow(row);
Add(oPost);
}
}
}
Now while this is working all well and good, I'm just wondering if there is any way to improve it, and just make it cleaner that having to use the two different classes do to something I think can happen in just one class or using an interface.
I've set up a query to return notes for every day. now only the first row (id=1) shows. I'd like visitors to the site to see the next row on the next day, and so forth.
I've modified an object dumping method to avoid circual references causing a StackOverflow error. This is what I ended up with:
//returns all fields of the given object in a string
public static String dumpFields(Object o, int callCount, ArrayList excludeList)
{
//add this object to the exclude list to avoid circual references in the future
if (excludeList == null) excludeList = new ArrayList();
excludeList.add(o);
callCount++;
StringBuffer tabs = new StringBuffer();
for (int k = 0; k < callCount; k++)
{
tabs.append("\t");
}
StringBuffer buffer = new StringBuffer();
Class oClass = o.getClass();
if (oClass.isArray()) {
buffer.append("\n");
buffer.append(tabs.toString());
buffer.append("[");
for (int i = 0; i < Array.getLength(o); i++)
{
if (i < 0) buffer.append(",");
Object value = Array.get(o, i);
if (value != null)
{
if (excludeList.contains(value))
{
buffer.append("circular reference");
}
else if (value.getClass().isPrimitive() || value.getClass() == java.lang.Long.class || value.getClass() == java.lang.String.class || value.getClass() == java.lang.Integer.class || value.getClass() == java.lang.Boolean.class)
{
buffer.append(value);
}
else
{
buffer.append(dumpFields(value, callCount, excludeList));
}
}
}
buffer.append(tabs.toString());
buffer.append("]\n");
}
else
{
buffer.append("\n");
buffer.append(tabs.toString());
buffer.append("{\n");
while (oClass != null)
{
Field[] fields = oClass.getDeclaredFields();
for (int i = 0; i < fields.length; i++)
{
if (fields[i] == null) continue;
buffer.append(tabs.toString());
fields[i].setAccessible(true);
buffer.append(fields[i].getName());
buffer.append("=");
try
{
Object value = fields[i].get(o);
if (value != null)
{
if (excludeList.contains(value))
{
buffer.append("circular reference");
}
else if ((value.getClass().isPrimitive()) || (value.getClass() == java.lang.Long.class) || (value.getClass() == java.lang.String.class) || (value.getClass() == java.lang.Integer.class) || (value.getClass() == java.lang.Boolean.class))
{
buffer.append(value);
}
else
{
buffer.append(dumpFields(value, callCount, excludeList));
}
}
}
catch (IllegalAccessException e)
{
System.out.println("IllegalAccessException: " + e.getMessage());
}
buffer.append("\n");
}
oClass = oClass.getSuperclass();
}
buffer.append(tabs.toString());
buffer.append("}\n");
}
return buffer.toString();
}
The method is initially called like this:
System.out.println(dumpFields(obj, 0, null);
So, basically I added an excludeList which contains all the previousely checked objects. Now, if an object contains another object and that object links back to the original object, it should not follow that object further down the chain.
However, my logic seems to have a flaw as I still get stuck in an infinite loop. Does anyone know why this is happening?
I just started playing with Clojure, and I wrote a small script to help me understand some of the functions. It begins like this:
(def *exprs-to-test* [
"(filter #(< % 3) '(1 2 3 4 3 2 1))"
"(remove #(< % 3) '(1 2 3 4 3 2 1))"
"(distinct '(1 2 3 4 3 2 1))"
])
Then it goes through *exprs-to-test*, evaluates them all, and prints the output like this:
(doseq [exstr *exprs-to-test*]
(do
(println "===" (first (read-string exstr)) "=========================")
(println "Code: " exstr)
(println "Eval: " (eval (read-string exstr)))
)
)
The above code is all working fine. However, (read-string exstr) is repeated so I tried to use let to eliminate the repetition like so:
(doseq [exstr *exprs-to-test*]
(let [ex (read-string exstr)] (
(do
(println "===" (first ex) "=========================")
(println "Code: " exstr)
(println "Eval: " (eval ex))
)
))
)
But this works once for the first item in *exprs-to-test*, then crashes with a NullPointerException. Why is the addition of let causing the crash?
I'm working on Euler Problem 14:
http://projecteuler.net/index.php?section=problems&id=14
I figured the best way would be to create a vector of numbers that kept track of how big the series was for that number... for example from 5 there are 6 steps to 1, so if ever reach the number 5 in a series, I know I have 6 steps to go and I have no need to calculate those steps. With this idea I coded up the following:
#include <iostream>
#include <vector>
#include <iomanip>
using namespace std;
int main()
{
vector<int> sizes(1);
sizes.push_back(1);
sizes.push_back(2);
int series, largest = 0, j;
for (int i = 3; i <= 1000000; i++)
{
series = 0;
j = i;
while (j > (sizes.size()-1))
{
if (j%2)
{
j=(3*j+1)/2;
series+=2;
}
else
{
j=j/2;
series++;
}
}
series+=sizes[j];
sizes.push_back(series);
if (series>largest)
largest=series;
cout << setw(7) << right << i << "::" << setw(5) << right << series << endl;
}
cout << largest << endl;
return 0;
}
It seems to work relatively well for smaller numbers but this specific program stalls at the number 113382. Can anyone explain to me how I would go about figuring out why it freezes at this number?
Is there some way I could modify my algorithim to be better? I realize that I am creating duplicates with the current way I'm doing it:
for example, the series of 3 is 3,10,5,16,8,4,2,1. So I already figured out the sizes for 10,5,16,8,4,2,1 but I will duplicate those solutions later.
Thanks for your help!
Some points that make java swing layout system a nightmare:
There's thousands of properties;
Even if you learn all the properties, each layout manager ignores some properties;
The only existing good RAD tool (NetBeans) does not work well;
Layout managers behave different with components and containers inside it.
I've been following a lot of good tutorials on building rails apps but I seem to be missing the whole specifying and validating db field sizes part. I love not needing to have to think about it when roughing out an app (I would have never done this with a PHP or ASP.net app). However, now that I'm ready to go to production, I think I might have done myself a disservice by not specifying field sizes as I went. My production db will be MySQL. What is the best practice here? Do I need to go through all of my migration files and specify sizes, update all the models with validation, and update all my form partial views with input max widths? or am I missing a critical step in my development process?
Hi all,
I'm using MEF and the System.ComponentModel.Composition.dll to load some dll.
I'm doing something like :
AggregateCatalog catalog = new AggregateCatalog(new AssemblyCatalog(Assembly.GetExecutingAssembly()), new DirectoryCatalog(directory));
_container = new CompositionContainer(catalog);
_container.ComposeParts(this);
to import my dll.
After some times, I would like to update my dll but if I try to delete it, I have an access denied, because it's alrealdy used by the program.
How can I release the dll, replace with a new dll and load the dll again ? (without closing the program)
Thanks in advance for your help
Still early days with Mathematica so please forgive what is probably a very obvious question. I am trying to generate some parametric plots. I have:
ParametricPlot[{
(a + b) Cos[t] - h Cos[(a + b)/b t],
(a + b) Sin[t] - h Sin[(a + b)/b t]},
{t, 0, 2 \[Pi]}, PlotRange -> All] /. {a -> 2, b -> 1, h -> 1}
No joy: the replacement rules are not applied and a, b and h remain undefined.
If I instead do:
Hold@ParametricPlot[{
(a + b) Cos[t] - h Cos[(a + b)/b t],
(a + b) Sin[t] - h Sin[(a + b)/b t]},
{t, 0, 2 \[Pi]}, PlotRange -> All] /. {a -> 2, b -> 1, h -> 1}
it looks like the rules ARE working, as confirmed by the output:
Hold[ParametricPlot[{(2 + 1) Cos[t] -
1 Cos[(2 + 1) t], (2 + 1) Sin[t] - 1 Sin[(2 + 1) t]}, {t, 0,
2 \[Pi]}, PlotRange -> All]]
Which is what I'd expect. Take the Hold off, though, and the ParametricPlot doesn't work. There's nothing wrong with the equations or the ParametricPlot itself, though, because I tried setting values for a, b and h in a separate expression (a=2; b=1; h=1) and I get my pretty double cardoid out as expected.
So, what am I doing wrong with ReplaceAll and why are the transformation rules not working? This is another fundamentally important aspect of MMA that my OOP-ruined brain isn't understanding.
I tried reading up on ReplaceAll and ParametricPlot and the closest clue I found was that "ParametricPlot has attribute HoldAll and evaluates f only after assigning specific numerical values to variables" which didn't help much or I wouldn't be here.
Thanks.
The following test fails:
(ns clojure_refactoring.rename-fn-test
(:use clojure.test))
(deftest test-fn-location
(in-ns 'refactoring-test-fn-rename)
(clojure.core/refer-clojure)
(defn a [b] (inc b))
(in-ns 'clojure_refactoring.rename-fn-test)
(is (not= (find-var 'refactoring-test-fn-rename/a)
nil))
(remove-ns 'refactoring-test-fn-rename))
That is, find-var (of a var I've just created, in a namespace I've just create) returns nil. This behaviour doesn't happen at the repl, where typing out the steps of the test works just fine.
Am I doing something wrong, or is this just something that doesn't work in clojure right now?
I tried to backport a Python 3 program to 2.7, and I'm stuck with a strange problem:
>>> import io
>>> import csv
>>> output = io.StringIO()
>>> output.write("Hello!") # Fail: io.StringIO expects Unicode
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unicode argument expected, got 'str'
>>> output.write(u"Hello!") # This works as expected.
6L
>>> writer = csv.writer(output) # Now let's try this with the csv module:
>>> csvdata = [u"Hello", u"Goodbye"] # Look ma, all Unicode! (?)
>>> writer.writerow(csvdata) # Sadly, no.
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unicode argument expected, got 'str'
According to the docs, io.StringIO() returns an in-memory stream for Unicode text. It works correctly when I try and feed it a Unicode string manually. Why does it fail in conjunction with the csv module, even if all the strings being written are Unicode strings? Where does the str come from that causes the Exception?
(I do know that I can use StringIO.StringIO() instead, but I'm wondering what's wrong with io.StringIO() in this scenario)
I've got VS2010 and im pretty sure .NET 4.0, as if i try to install it from MS it says do i wish to repair the current version- so i must have it. But i want to create a concurrent dictionary and i cant seem to find the correct packet. I went to references to add it manually but it wasnt in my list?
I have a home page that has several independent dynamic parts. The parts consist of a list of recent news from the company, a site statistics panel, and the online status of certain employees. The recent news changes monthly, site statistics change daily, and online statuses change on a per minute bases. I would like to cache these panels so that the db is not hit on every page load.
Is using ob_start() then ob_get_contents() to cache these parts to a file the correct way to do this or is there a better method in PHP5 for doing this?
In asking this question I'm trying to answer these additional questions:
How can I determine the correct approach for caching this data without doing extensive benchmarking?
Does it make sense to cache these parts in different files and then join them together per requests or should I re-query the data and cache once per minute?
I'm looking for a rule of thumb for planning pages and for situations where doing testing is not cost effective (The client is not paying enough for it I mean).
Thanks!
I'm considering if it is a good idea to use an ASP.Net TabContainer-Control in the way that every TabPanel contains content of a different page. For example: Next i want to implement in my application is the masterdata management. Normally i would create one aspx page for every masterdata-table (f.e. Customer - MD_Customer.aspx). Then i would add a link into my Menu to this page.
Now i'm thinking of creating one aspx page for all(Masterdata.aspx) with a Tabcontainer and an UpdatePanel for every type of Masterdata. The link it the menu could have an additional MDType as URL-Parameter.
My main concerns are related to performance(one "page" for every TabPanel currently means 7 "pages" in one) and maintainability because of increasing complexity.
Is it a good approach or a bad idea?
Thanks
We are a team of many developers working on a website that uses both Joomla and custom PHP scripts. The problem is that there are multiple developers working on various features which need to update information in Joomla (adding modules, changing existing ones or changing settings) and when one developer changes something, he usually makes the change locally first and then does the same thing (hopefully) on the production server. Not only that this is very error-prone, but the developers often forget to tell other developers about the changes. The custom PHP scripts are easily shared between developers, but the changes in Joomla are often forgotten and they lead to serious conflicts when a developer tries to replicate his local changes in production.
I have thought about placing Joomla in a Mercurial repository, but how could we distribute the changes in the database between the development, the testing and the production machines?
I have the following bash code, which is copied and pasted from "bash cookbook" (1st edition):
#!/bin/bash
VERBOSE=0;
if [[ $1 =-v ]]
then
VERBOSE=1;
shift;
fi
When I run this (bash 4.0.33), I get the following syntax error:
./test.sh: line 4: conditional binary operator expected
./test.sh: line 4: syntax error near `=-v'
./test.sh: line 4: `if [[ $1 =-v ]]'
Is this as simple as a misprint in the bash cookbook, or is there a version incompatibility or something else here? What would the most obvious fix be? I've tried various combinations of changing the operator, but I'm not really familiar with bash scripting.
I have installed MAMP and the PHP it came with wasn't compiled with ncurses. I've tried to use port to install ncurses and it seems that it already exists on my system so now I was wondering if there was a way to get PHP to use it without having to recompile PHP --with-ncurses.
In other words: Can PHP be configured to use ncurses without the recompilation?
Hey guys, im looking for some advice on how to properly structure the workflow for my team with git & github. we are recent svn converts and its kind of confusing on how we should best setup our day-to-day workflow. Here is a little background, im comfortable with command line and my team is pretty new to it but can follow use commands. We all are working on the same project with 3 environments (development, staging, and production). We are a mix of developers & designers so some use the Git GUI and some command line.
Our setup in svn went something like this. We had a branch for development, staging and production. When people were confident with code they would commit and then merge it into the staging. The server would update itself and on a release day (weekly) we would do a diff and push the changes to the production server. Now i setup those branches and got the process with the server running but its the actual workflow that is confusing the hell out of me.
It seems like overkill that every time someone makes a change on a file they would create a new branch, commit, merge, and delete that branch... from what i have read they would be able to do it on a specific commit (using the hash), do i have that right? is this an acceptable way to go about things with git? any advice would be greatly appreciated.