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How assignment works with Python list slice?
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4 Answers
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Pandas get topmost n records within each group
... value
id
1 0 1 1
1 1 2
2 3 2 1
4 2 2
3 7 3 1
4 8 4 1
(Keep in mind that you might need to order/sort before, depending on your data)
EDIT: As mentioned by the questioner, use df.groupby('id').head(2).reset_index(drop=True) to remo...
How does zip(*[iter(s)]*n) work in Python?
... zip(), and it pulls an item from the iterator each time.
x = iter([1,2,3,4,5,6,7,8,9])
print zip(x, x, x)
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How do I forward parameters to other command in bash script?
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245
Use the shift built-in command to "eat" the arguments. Then call the child process and pass it ...
What is the significance of initializing direction arrays below with given values when developing ch
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84
This is a technique to encode all directions as arrays - every pair of di[i],dj[i] is a differen...
What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?
... -8388608 to 8388607 0 to 16777215
int/integer | 4 bytes -2147483648 to 2147483647 0 to 4294967295
bigint | 8 bytes -9223372036854775808 to 9223372036854775807 0 to 18446744073709551615
The "unsigned" types are only available in MySQL, and the ...
Replacing NAs with latest non-NA value
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164
You probably want to use the na.locf() function from the zoo package to carry the last observati...
Extract elements of list at odd positions
... second at 1 etc.):
1, 3, 5
so the result (actual numbers) will be:
2, 4, 6
Explanation
The [1::2] at the end is just a notation for list slicing. Usually it is in the following form:
some_list[start:stop:step]
If we omitted start, the default (0) would be used. So the first element (at po...
Backporting Python 3 open(encoding=“utf-8”) to Python 2
...tions.html#open.
– pmdarrow
Oct 9 '14 at 18:34
7
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PHP: merge two arrays while keeping keys instead of reindexing?
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564
You can simply 'add' the arrays:
>> $a = array(1, 2, 3);
array (
0 => 1,
1 => 2...