大约有 900 项符合查询结果（耗时：0.0156秒） [XML]
Is there a way to make R beep/play a sound at the end of a script?
...ered Jul 1 '14 at 18:08
Rasmus BååthRasmus Bååth
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What is your preferred style for naming variables in R? [closed]
...ered Nov 16 '12 at 8:55
Rasmus BååthRasmus Bååth
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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
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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...
Determine the line of code that causes a segmentation fault?
...rite tool to the list: Address Sanitizers (often abbreviated ASAN).
Modern¹ compilers come with the handy -fsanitize=address flag, adding some compile time and run time overhead which does more error checking.
According to the documentation these checks include catching segmentation faults by def...
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...
Difference between single and double square brackets in Bash
...Bash 4.3.11:
POSIX vs Bash extension:
[ is POSIX
[[ is a Bash extension¹ documented at: https://www.gnu.org/software/bash/manual/bash.html#Conditional-Constructs
regular command vs magic
[ is just a regular command with a weird name.
] is just an argument of [ that prevents further argument...
Does PostgreSQL support “accent insensitive” collations?
... unaccent() always substitutes a single letter:
SELECT unaccent('Œ Æ œ æ ß');
unaccent
----------
E A e a S
You will love this update to unaccent in Postgres 9.6:
Extend contrib/unaccent's standard unaccent.rules file to handle all
diacritics known to Unicode, and expand ligatures cor...
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
...