大约有 800 项符合查询结果（耗时：0.0216秒） [XML]
How to extract the n-th elements from a list of tuples?
...ray(elements)[:,1]
and the timings:
list comprehension: 4.73 ms ± 206 µs per loop
list(map): 5.3 ms ± 167 µs per loop
dict: 2.25 ms ± 103 µs per loop
list(zip) 5.2 ms ± 252 µs per loop
numpy array: 28.7 ms ± 1.88 ms per loop
Note that map() a...
Find the most frequent number in a numpy vector
...t collections.Counter(a).most_common()[0][0]
100000 loops, best of 3: 11.3 µs per loop
>>>
>>> import numpy
>>> numpy.bincount(a).argmax()
3
>>> %timeit numpy.bincount(a).argmax()
100 loops, best of 3: 2.84 ms per loop
>>>
>>> import scipy.sta...
Replace all elements of Python NumPy Array that are greater than some value
...r case:
In [292]: timeit np.minimum(a, 255)
100000 loops, best of 3: 19.6 µs per loop
In [293]: %%timeit
.....: c = np.copy(a)
.....: c[a>255] = 255
.....:
10000 loops, best of 3: 86.6 µs per loop
If you want to do it in-place (i.e., modify arr instead of creating result) you can ...
Improving bulk insert performance in Entity framework [duplicate]
... answered Nov 6 '13 at 12:21
Måns TånnerydMåns Tånneryd
47344 silver badges88 bronze badges
...
How to reset index in a pandas dataframe? [duplicate]
...n that an intermediate result is being cached.
10000 loops, best of 3: 105 µs per loop
In [299]: %timeit df.index = pd.RangeIndex(len(df.index))
The slowest run took 15.05 times longer than the fastest. This could mean that an intermediate result is being cached.
100000 loops, best of 3: 7.84 µs ...
DateTime.ToString(“MM/dd/yyyy HH:mm:ss.fff”) resulted in something like “09/14/2013 07.20.31.371”
... answered Sep 2 '15 at 8:06
Håkon SeljåsenHåkon Seljåsen
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...
Numpy: find first index of value fast
...e(100000)
%timeit index(arr, 5) # 1000000 loops, best of 3: 1.88 µs per loop
%timeit find_first(5, arr) # 1000000 loops, best of 3: 1.7 µs per loop
%timeit index(arr, 99999) # 10000 loops, best of 3: 118 µs per loop
%timeit find_first(99999, arr) # 10000 loops, best of 3: 9...
Approximate cost to access various caches and main memory?
... Mutex lock/unlock
100 ns Main memory (RAM)
2 000 ns (2µs) 1KB Zippy-compress
Still some improvements, prediction for 2020
16 000 ns (16µs) SSD random read (olibre's note: should be less)
500 000 ns (½ms) Round trip in datacenter
2 000 000 ns (2ms) HDD random read (s...
Remove rows with duplicate indices (Pandas DataFrame and TimeSeries)
...>> %timeit df3.groupby(df3.index).first()
1000 loops, best of 3: 580 µs per loop
>>> %timeit df3[~df3.index.duplicated(keep='first')]
1000 loops, best of 3: 307 µs per loop
Note that you can keep the last element by changing the keep argument to 'last'.
It should also be noted tha...
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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