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Python idiom to return first item or None
I'm sure there's a simpler way of doing this that's just not occurring to me.
23 Answers
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What does ||= (or-equals) mean in Ruby?
...gnment operator. It means if a is undefined or falsey, then evaluate b and set a to the result. Equivalently, if a is defined and evaluates to truthy, then b is not evaluated, and no assignment takes place. For example:
a ||= nil # => nil
a ||= 0 # => 0
a ||= 2 # => 0
foo = false # => ...
What's the purpose of the LEA instruction?
...tain computations, but that's not its primary purpose. The x86 instruction set was designed to support high-level languages like Pascal and C, where arrays—especially arrays of ints or small structs—are common. Consider, for example, a struct representing (x, y) coordinates:
struct Point
{
...
How to discard all changes made to a branch?
... ) and I've made a number of changes, but I need to discard them all and reset it to match the repository version. I thought git checkout design would do it, but it just tells me I'm already in branch design and that I have 3 modified files.
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Oracle取前N条记录方法 Oracle实现SELECT TOP N的方法 - 爬虫/数据库 - 清...
select * from ( select * from tablexxx order by xxx desc ) where rownum <= N
oracle数据库不支持mysql中limit, top功能,但可以通过rownum来限制返回的结果集的行数,rownum并不是用户添加的字段,而是oracle系统自动添加的。
String replacement in Objective-C
...multiple string replacement:
NSString *s = @"foo/bar:baz.foo";
NSCharacterSet *doNotWant = [NSCharacterSet characterSetWithCharactersInString:@"/:."];
s = [[s componentsSeparatedByCharactersInSet: doNotWant] componentsJoinedByString: @""];
NSLog(@"%@", s); // => foobarbazfoo
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Javascript How to define multiple variables on a single line?
...o lines?
var a, b, c, d; // All in the same scope
a = b = c = d = 1; // Set value to all.
The reason why, is to preserve the local scope on variable declarations, as this:
var a = b = c = d = 1;
will lead to the implicit declarations of b, c and d on the window scope.
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Use HTML5 to resize an image before upload
...sizeImageOptions {
maxSize: number;
file: File;
}
const resizeImage = (settings: IResizeImageOptions) => {
const file = settings.file;
const maxSize = settings.maxSize;
const reader = new FileReader();
const image = new Image();
const canvas = document.createElement('canvas');
con...
How do I make a redirect in PHP?
... click $link here if redirect dont happen" Some broser, and some browser's settings, may fail that redirect.
– Strae
Apr 20 '09 at 15:49
3
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What does 'wb' mean in this code, using Python?
... editor after snippets, if snippets enabled
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