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Iterate a list with indexes in Python
...ld swear I've seen the function (or method) that takes a list, like this [3, 7, 19] and makes it into iterable list of tuples, like so: [(0,3), (1,7), (2,19)] to use it instead of:
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Fastest way to check if a string matches a regexp in ruby?
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answered Mar 16 '17 at 12:30
Wiktor StribiżewWiktor Stribiżew
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How to convert a data frame column to numeric type?
...ac num
1 a 1 1 a 1
2 b 2 2 b 2
3 c 3 3 c 3
4 d 4 4 d 4
5 e 5 5 e 5
and let us run:
> sapply(d, mode)
char fake_char fac char_fac num
"character" "character...
while (1) vs. while(True) — Why is there a difference (in python 2 bytecode)?
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3 Answers
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Why are Python lambdas useful? [closed]
...where you can pass functions to other functions to do stuff. Example:
mult3 = filter(lambda x: x % 3 == 0, [1, 2, 3, 4, 5, 6, 7, 8, 9])
sets mult3 to [3, 6, 9], those elements of the original list that are multiples of 3. This is shorter (and, one could argue, clearer) than
def filterfunc(x):
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Comparing two dictionaries and checking how many (key, value) pairs are equal
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edited Jun 14 '18 at 13:15
Olivier Melançon
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Deleting an element from an array in PHP
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38 Answers
38
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Python, compute list difference
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373
If the order does not matter, you can simply calculate the set difference:
>>> set([...
How assignment works with Python list slice?
...ete, or replace contents from a list:
Insertion:
>>> a = [1, 2, 3]
>>> a[0:0] = [-3, -2, -1, 0]
>>> a
[-3, -2, -1, 0, 1, 2, 3]
Deletion:
>>> a
[-3, -2, -1, 0, 1, 2, 3]
>>> a[2:4] = []
>>> a
[-3, -2, 1, 2, 3]
Replacement:
>>> a
[-...
How do I exchange keys with values in a dictionary?
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Python 2:
res = dict((v,k) for k,v in a.iteritems())
Python 3 (thanks to @erik):
res = dict((v,k) for k,v in a.items())
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