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Python, compute list difference
... the order does not matter, you can simply calculate the set difference:
>>> set([1,2,3,4]) - set([2,5])
set([1, 4, 3])
>>> set([2,5]) - set([1,2,3,4])
set([5])
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Why can't I make a vector of references?
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The component type of containers like vectors must be assignable. References are not assignable (you can only initialize them once when they are declared, and you cannot make them reference something else later). Other non-assignable types are also not allowed as components of conta...
Remove all whitespaces from NSString
I've been trying to get rid of the white spaces in an NSString , but none of the methods I've tried worked.
11 Answers
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How to profile a bash shell script slow startup?
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If you have GNU date (or another version that can output nanoseconds), do this at the beginning of /etc/bash.bashrc (or wherever you'd like to begin a trace in any Bash script):
PS4='+ $(date "+%s.%N")\011 '
exec 3>&2 2>/tmp/b...
Why is Dictionary preferred over Hashtable in C#?
In most programming languages, dictionaries are preferred over hashtables.
What are the reasons behind that?
19 Answers
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How to format current time using a yyyyMMddHHmmss format?
I'm trying to format the current time using this format yyyyMMddHHmmss .
4 Answers
4
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How to check if a URL is valid
How can I check if a string is a valid URL?
9 Answers
9
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How to delete duplicate lines in a file without sorting it in Unix?
...ne isn't in the array then seen[$0] will evaluate to false. The ! is the logical NOT operator and will invert the false to true. Awk will print the lines where the expression evaluates to true. The ++ increments seen so that seen[$0] == 1 after the first time a line is found and then seen[$0] == 2, ...
Limiting floats to two decimal points
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You are running into the old problem with floating point numbers that not all numbers can be represented exactly. The command line is just showing you the full floating point form from memory.
With floating point representation, your roun...
Create a custom callback in JavaScript
... your code will pretty much work as is, just declare your callback as an argument and you can call it directly using the argument name.
The basics
function doSomething(callback) {
// ...
// Call the callback
callback('stuff', 'goes', 'here');
}
function foo(a, b, c) {
// I'm the ...