大约有 40,000 项符合查询结果（耗时：0.0358秒） [XML]
What is /dev/null 2>&1?
...
>> /dev/null redirects standard output (stdout) to /dev/null, which discards it.
(The >> seems sort of superfluous, since >> means append while > means truncate and write, and either appending to or writi...
How to check whether a file is empty or not?
...
>>> import os
>>> os.stat("file").st_size == 0
True
share
|
improve this answer
|
...
How to extract the n-th elements from a list of tuples?
...g this, to prove to myself that I have groked zip...)
See it in action:
>>> help(zip)
Help on built-in function zip in module builtin:
zip(...)
zip(seq1 [, seq2 [...]]) -> [(seq1[0], seq2[0] ...), (...)]
Return a list of tuples, where each tuple contains the i-th el...
Calling closure assigned to object property directly
...
As of PHP7, you can do
$obj = new StdClass;
$obj->fn = function($arg) { return "Hello $arg"; };
echo ($obj->fn)('World');
or use Closure::call(), though that doesn't work on a StdClass.
Before PHP7, you'd have to implement the magic __call method to intercept the ...
Is there a NumPy function to return the first index of something in an array?
...s the array is 2D. where works on any array, and will return a tuple of length 3 when used on a 3D array, etc.
– P. Camilleri
Jul 5 '17 at 7:52
|
...
How do I calculate the date six months from the current date using the datetime Python module?
...th+6)/12) can buggy, as it generates invalid dates such as (31, 8, 2015) -> (31, 2, 2016)
– ohw
Jan 16 '16 at 23:40
|
show 4 more comment...
Good MapReduce examples [closed]
...e In SQL, Given the Date of Birth, to find out How many people are of age > 30 for a million records would take a while, and this would only increase in order of magnitute when the complexity of the query increases.
Map Reduce provides a cluster based implementation where data is processed in a ...
Find row where values for column is maximal in a pandas DataFrame
...
Use the pandas idxmax function. It's straightforward:
>>> import pandas
>>> import numpy as np
>>> df = pandas.DataFrame(np.random.randn(5,3),columns=['A','B','C'])
>>> df
A B C
0 1.232853 -1.979459 -0.573626
1 0.140...
Convert timedelta to total seconds
...
Use timedelta.total_seconds().
>>> import datetime
>>> datetime.timedelta(seconds=24*60*60).total_seconds()
86400.0
share
|
improve this...
Doing HTTP requests FROM Laravel to an external API
...
Take a look at Guzzle
$client = new GuzzleHttp\Client();
$res = $client->get('https://api.github.com/user', ['auth' => ['user', 'pass']]);
echo $res->getStatusCode(); // 200
echo $res->getBody(); // { "type": "User", ....
...