大约有 40,000 项符合查询结果（耗时：0.0382秒） [XML]
How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
...and any to build a boolean Series and use that to index into your frame:
>>> df = pd.DataFrame([range(3), [0, np.NaN, 0], [0, 0, np.NaN], range(3), range(3)])
>>> df.isnull()
0 1 2
0 False False False
1 False True False
2 False False True
3 False Fals...
What can I use instead of the arrow operator, `->`?
What is the arrow operator ( -> ) a synonym for?
7 Answers
7
...
partial string formatting
... '{foo} {{bar}}'
Use it like this:
ss = s.format(foo='FOO')
print ss
>>> 'FOO {bar}'
print ss.format(bar='BAR')
>>> 'FOO BAR'
You can't specify foo and bar at the same time - you have to do it sequentially.
...
Mocking python function based on input arguments
... to vary the return
value of the call dynamically, based on the input:
>>> def side_effect(value):
... return value + 1
...
>>> m = MagicMock(side_effect=side_effect)
>>> m(1)
2
>>> m(2)
3
>>> m.mock_calls
[call(1), call(2)]
http://www.voidspace...
Check if string ends with one of the strings from a list
...widely known, str.endswith also accepts a tuple. You don't need to loop.
>>> 'test.mp3'.endswith(('.mp3', '.avi'))
True
share
|
improve this answer
|
follow
...
How to reformat JSON in Notepad++?
...ed directly from the built in "Plugin Manager" in Notepad++. Go "Plugins > Plugin Manager > Show Plugin Manager > Available tab"
– Dib
Feb 24 '16 at 15:30
...
What is the difference between RegExp’s exec() function and String’s match() function?
...gex is not global, but doesn't show captures when the regex is global.
> "azb".match(/a(z)b/);
[ "azb", "z" ]
> "azb".match(/a(z)b/g);
[ "azb" ]
>
Another thing is that if you use exec, note that's called on the regex, then if you used a variable for the regex, you have more power
Yo...
How to skip over an element in .map()?
...s a single simple intention, which is to create a new array of the same length as an old array, only with values formed by a transformation of the old values.
share
|
improve this answer
|
...
Multiple levels of 'collection.defaultdict' in Python
... Number):
return -1 * x
raise ValueError
Examples:
>>> import autovivify
>>> a = autovivify.autovivify()
>>> a
{}
>>> a[2]
{}
>>> a
{2: {}}
>>> a[4] += 1
>>> a[5][3][2] -= 1
>>> a
{2: {}, 4: 1, 5: {3: {2: ...
round() doesn't seem to be rounding properly
...stions/9301690/…. Floating point inaccuracy is to blame here -- "5.665 -> 5.67" but "15.665 -> 15.66". Use decimals if you need exact precision.
– Jimmy
Jul 15 '15 at 22:42
...