大约有 45,000 项符合查询结果（耗时：0.0390秒） [XML]
`elif` in list comprehension conditionals
...s were designed exactly for this sort of use-case:
>>> l = [1, 2, 3, 4, 5]
>>> ['yes' if v == 1 else 'no' if v == 2 else 'idle' for v in l]
['yes', 'no', 'idle', 'idle', 'idle']
Hope this helps :-)
share
...
std::next_permutation Implementation Explanation
...
Let's look at some permutations:
1 2 3 4
1 2 4 3
1 3 2 4
1 3 4 2
1 4 2 3
1 4 3 2
2 1 3 4
...
How do we go from one permutation to the next? Firstly, let's look at things a little differently. We can view the elements as digits and the permutations as numbers. ...
How to find the installed pandas version
...
375
Check pandas.__version__:
In [76]: import pandas as pd
In [77]: pd.__version__
Out[77]: '0.1...
How assignment works with Python list slice?
...ete, or replace contents from a list:
Insertion:
>>> a = [1, 2, 3]
>>> a[0:0] = [-3, -2, -1, 0]
>>> a
[-3, -2, -1, 0, 1, 2, 3]
Deletion:
>>> a
[-3, -2, -1, 0, 1, 2, 3]
>>> a[2:4] = []
>>> a
[-3, -2, 1, 2, 3]
Replacement:
>>> a
[-...
How does zip(*[iter(s)]*n) work in Python?
... arguments for a function call. Therefore you're passing the same iterator 3 times to zip(), and it pulls an item from the iterator each time.
x = iter([1,2,3,4,5,6,7,8,9])
print zip(x, x, x)
share
|
...
How can I obtain the element-wise logical NOT of a pandas Series?
... True, False, True])
In [8]: ~s
Out[8]:
0 False
1 False
2 True
3 False
dtype: bool
Using Python2.7, NumPy 1.8.0, Pandas 0.13.1:
In [119]: s = pd.Series([True, True, False, True]*10000)
In [10]: %timeit np.invert(s)
10000 loops, best of 3: 91.8 µs per loop
In [11]: %timeit ~s
10...
How can I obtain an 'unbalanced' grid of ggplots?
...
73
grid.arrange draws directly on the device; if you want to combine it with other grid objects you...
Small Haskell program compiled with GHC into huge binary
...
Let's see what's going on, try
$ du -hs A
13M A
$ file A
A: ELF 64-bit LSB executable, x86-64, version 1 (SYSV),
dynamically linked (uses shared libs), for GNU/Linux 2.6.27, not stripped
$ ldd A
linux-vdso.so.1 => (0x00007fff1b9ff000)
libXr...
Confusion between factor levels and factor labels
...
131
Very short : levels are the input, labels are the output in the factor() function. A factor has...