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When NOT to call super() method when overriding?
...ustom class, I extend its native class. Then when I want to override the base method, I always call super() method, just like I always do in onCreate , onStop , etc.
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Call a function from another file?
...te from file import function, and then call the function using function(a, b). The reason why this may not work, is because file is one of Python's core modules, so I suggest you change the name of your file.
Note that if you're trying to import functions from a.py to a file called b.py, you will n...
XPath to select multiple tags
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One correct answer is:
/a/b/*[self::c or self::d or self::e]
Do note that this
a/b/*[local-name()='c' or local-name()='d' or local-name()='e']
is both too-long and incorrect. This XPath expression will select nodes like:
OhMy:c
NotWanted:d
Qu...
Adding a column to a data.frame
I have the data.frame below. I want to add a column that classifies my data according to column 1 ( h_no ) in that way that the first series of h_no 1,2,3,4 is class 1, the second series of h_no (1 to 7) is class 2 etc. such as indicated in the last column.
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Creating a “logical exclusive or” operator in Java
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Java does have a logical XOR operator, it is ^ (as in a ^ b).
Apart from that, you can't define new operators in Java.
Edit: Here's an example:
public static void main(String[] args) {
boolean[] all = { false, true };
for (boolean a : all) {
for (boolean b: all) ...
How to avoid explicit 'self' in Python?
I have been learning Python by following some pygame tutorials .
11 Answers
11
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Why does PHP 5.2+ disallow abstract static class methods?
After enabling strict warnings in PHP 5.2, I saw a load of strict standards warnings from a project that was originally written without strict warnings:
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How to count the frequency of the elements in an unordered list?
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Note: You should sort the list before using groupby.
You can use groupby from itertools package if the list is an ordered list.
a = [1,1,1,1,2,2,2,2,3,3,4,5,5]
from itertools import groupby
[len(list(group)) for key, group in groupby(a)]
Output:
[4, 4...
assign multiple variables to the same value in Javascript
I have initialized several variables in the global scope in a JavaScript file:
5 Answers
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Remove an item from a dictionary when its key is unknown
What is the best way to remove an item from a dictionary by value, i.e. when the item's key is unknown? Here's a simple approach:
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