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Numpy argsort - what is it doing?
...*2)
In [81]: %timeit using_argsort_twice(x)
100000 loops, best of 3: 3.45 µs per loop
In [79]: %timeit using_indexed_assignment(x)
100000 loops, best of 3: 4.78 µs per loop
In [80]: %timeit using_rankdata(x)
100000 loops, best of 3: 19 µs per loop
In [82]: %timeit using_digitize(x)
10000 loop...
How to truncate milliseconds off of a .NET DateTime
...nce is between 50% and about 100% depending on the runtime; net 4.7.2: 0.35µs vs 0.62 µs and core 3.1: 0.18 µs vs 0.12 µs that's micro-seconds (10^-6 seconds)
– juwens
Feb 3 at 15:55
...
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 ...
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 ...
In C# check that filename is *possibly* valid (not that it exists) [duplicate]
... edited Apr 30 '17 at 0:51
buræquete
12.5k44 gold badges3131 silver badges6262 bronze badges
answered Jan 7 '09 at 21:11
...
Difference between InvariantCulture and Ordinal string comparison
...iosyncrasies out there.
Ordinal 0 9 A Ab a aB aa ab ss Ä Äb ß ä äb ぁ あ ァ ア 亜 Ａ
IgnoreCase 0 9 a A aa ab Ab aB ss ä Ä äb Äb ß ぁ あ ァ ア 亜 Ａ
--------------------------------------------------------------------
InvariantCulture 0 9 a A Ａ ä Ä aa ab aB ...
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...