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Remove all the elements that occur in one list from another
...es exactly what you want and stores the result in l3:
l3 = [x for x in l1 if x not in l2]
l3 will contain [1, 6].
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How to test if list element exists?
I would like to test if an element of a list exists, here is an example
7 Answers
7
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How to check if an option is selected?
... what you are looking for:
$('#mySelectBox option').each(function() {
if($(this).is(':selected')) ...
The non jQuery (arguably best practice) way to do it would be:
$('#mySelectBox option').each(function() {
if(this.selected) ...
Although, if you are just looking for the selected value...
don't fail jenkins build if execute shell fails
...ild process, I am running a git commit as an execute shell step. However, if there are no changes in the workspace, Jenkins is failing the build. This is because git is returning an error code when there are no changes to commit. I'd like to either abort the build, or just mark it as unstable if t...
Performing Breadth First Search recursively
...s, to implement something that follows the semantics of BFS at some cost. If the cost of comparison is expensive but node traversal is cheap, then as @Simon Buchan did, you can simply run an iterative depth-first search, only processing the leaves. This would mean no growing queue stored in the he...
How to wait until an element exists?
...ionObserver((mutations) => {
mutations.forEach((mutation) => {
if (!mutation.addedNodes) return
for (let i = 0; i < mutation.addedNodes.length; i++) {
// do things to your newly added nodes here
let node = mutation.addedNodes[i]
}
})
})
observer.observe(documen...
How to calculate number of days between two given dates?
If I have two dates (ex. '8/18/2008' and '9/26/2008' ), what is the best way to get the number of days between these two dates?
...
Should import statements always be at the top of a module?
...s within a function will cause calls to that function to take longer.
So if you care about efficiency, put the imports at the top. Only move them into a function if your profiling shows that would help (you did profile to see where best to improve performance, right??)
The best reasons I've see...
Determine if 2 lists have the same elements, regardless of order? [duplicate]
...o be hashable; runtime will be in O(n), where n is the size of the lists.
If the elements are also unique, you can also convert to sets (same asymptotic runtime, may be a little bit faster in practice):
set(x) == set(y)
If the elements are not hashable, but sortable, another alternative (runtime...
Reimport a module in python while interactive
... object, so it must have been successfully imported before. This is useful if you have edited the module source file using an external editor and want to try out the new version without leaving the Python interpreter.
If running Python 3.4 and up, do import importlib, then do importlib.reload(name...