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How to check that a string is an int, but not a double, etc.?
PHP has an intval() function that will convert a string to an integer. However I want to check that the string is an integer beforehand, so that I can give a helpful error message to the user if it's wrong. PHP has is_int() , but that returns false for string like "2" .
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How to declare an array in Python?
...le = []
Now variable refers to an empty list*.
Of course this is an assignment, not a declaration. There's no way to say in Python "this variable should never refer to anything other than a list", since Python is dynamically typed.
*The default built-in Python type is called a list, not an arr...
Tree data structure in C#
I was looking for a tree or graph data structure in C# but I guess there isn't one provided. An Extensive Examination of Data Structures Using C# 2.0 explains a bit about why. Is there a convenient library which is commonly used to provide this functionality? Perhaps through a strategy pattern t...
“for loop” with two variables? [duplicate]
...a nested for loop, use:
import itertools
for i, j in itertools.product(range(x), range(y)):
# Stuff...
If you just want to loop simultaneously, use:
for i, j in zip(range(x), range(y)):
# Stuff...
Note that if x and y are not the same length, zip will truncate to the shortest list. As...
Remove duplicates in the list using linq
...match on only some of the properties, create a custom equality comparer, e.g.:
class DistinctItemComparer : IEqualityComparer<Item> {
public bool Equals(Item x, Item y) {
return x.Id == y.Id &&
x.Name == y.Name &&
x.Code == y.Code &&...
Drawing a dot on HTML5 canvas [duplicate]
Drawing a line on the HTML5 canvas is quite straightforward using the context.moveTo() and context.lineTo() functions.
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javascript regex - look behind alternative?
Here is a regex that works fine in most regex implementations:
6 Answers
6
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In c# what does 'where T : class' mean?
In C# what does where T : class mean?
10 Answers
10
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What is a “context bound” in Scala?
One of the new features of Scala 2.8 are context bounds. What is a context bound and where is it useful?
4 Answers
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C＋＋模板的特化 - C/C++ - 清泛网 - 专注C/C++及内核技术
...不受任何约束的模板参数，或受到特定的修饰（例如const或者摇身一变成为了指针之类的东东，甚至是经过别的模板类包装之后的模板类型）或完全被指定了下来。
这是网上某个人的一些看法：
模板有两种特化，全特化和偏...