大约有 800 项符合查询结果（耗时：0.0081秒） [XML]
Add single element to array in numpy
...
for k in range(int(10e4)):
d.append(k)
f = np.array(d)
13.5 ms ± 277 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
Pre-allocating numpy array:
e = np.zeros((n,))
for k in range(n):
e[k] = k
9.92 ms ± 752 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
When the...
pypi UserWarning: Unknown distribution option: 'install_requires'
...ed Nov 28 '11 at 15:38
Fredrik HåårdFredrik Håård
2,4622020 silver badges3232 bronze badges
...
Delete rows from a pandas DataFrame based on a conditional expression involving len(string) giving K
...than raw column based filtration:-
%timeit df_new = df[(df.E>0)]
345 µs ± 10.5 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
%timeit dft.drop(dft[dft.E < 0].index, inplace=True)
890 µs ± 94.9 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
A column is basical...
Efficiently replace all accented characters in a string?
...
"à":"a",
"ả":"a",
"ȃ":"a",
"ā":"a",
"ą":"a",
"ᶏ":"a",
"ẚ":"a",
"å":"a",
"ǻ":"a",
"ḁ":"a",
"ⱥ":"a",
"ã":"a",
"ꜳ":"aa",
"æ":"ae",
"ǽ":"ae",
"ǣ":"ae",
"ꜵ":"ao",
"ꜷ":"au",
"ꜹ":"av",
"ꜻ":"av",
"ꜽ":"ay",
"ḃ":"b",
"ḅ":"b",
"ɓ":"b",
"ḇ":"b",
"ᵬ":"b",
"ᶀ":"b",
"ƀ"...
Extract subset of key-value pairs from Python dictionary object?
...works in 2.7 too):
{k: bigdict[k] for k in ('l', 'm', 'n')}
Update: As Håvard S points out, I'm assuming that you know the keys are going to be in the dictionary - see his answer if you aren't able to make that assumption. Alternatively, as timbo points out in the comments, if you want a key tha...
Modifying a subset of rows in a pandas dataframe
...ings
%timeit df['b'] = np.where(df.a.values == 0, np.nan, df.b.values)
685 µs ± 6.4 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
%timeit df.loc[df['a'] == 0, 'b'] = np.nan
3.11 ms ± 17.2 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
Numpy's where is about 4x faster
...
Check if something is (not) in a list in Python
... 0.613 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
178 µs ± 5.01 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)
If you want to do more than just check whether an item is in a list, there are options:
list.index can be used to retrieve the index of an item. If t...
.gitignore is ignored by Git
...red Mar 19 '14 at 23:40
H AßdøµH Aßdøµ
2,31033 gold badges1414 silver badges2424 bronze badges
...
Python string class like StringBuilder in C#?
...]: %%timeit
...: ''.join(values)
...:
100000 loops, best of 3: 7.37 µs per loop
In [3]: %%timeit
...: result = ''
...: for value in values:
...: result += value
...:
10000 loops, best of 3: 82.8 µs per loop
In [4]: import io
In [5]: %%timeit
...: writer = io.StringIO(...
Replace values in list using Python [duplicate]
....: if not (item % 2):
...: items[index] = None
...:
1.06 µs ± 33.7 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
In [2]: %%timeit
...: items = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
...: new_items = [x if x % 2 else None for x in items]
...:
891 ns ± 13.6 n...