大约有 47,000 项符合查询结果（耗时：0.0427秒） [XML]
Python - abs vs fabs
...(-2))
Out[7]: int
In [8]: type(abs(-2.0))
Out[8]: float
In [9]: type(abs(3+4j))
Out[9]: float
In [10]: type(math.fabs(-2))
Out[10]: float
In [11]: type(math.fabs(-2.0))
Out[11]: float
In [12]: type(math.fabs(3+4j))
---------------------------------------------------------------------------
Type...
All possible array initialization syntaxes
...s above, the first two could replace the string[] on the left with var (C# 3+), as the information on the right is enough to infer the proper type. The third line must be written as displayed, as array initialization syntax alone is not enough to satisfy the compiler's demands. The fourth could also...
How to perform element-wise multiplication of two lists?
...gahooagahooa
108k1212 gold badges8686 silver badges9393 bronze badges
9
...
Numpy: Get random set of rows from 2D array
...
>>> A = np.random.randint(5, size=(10,3))
>>> A
array([[1, 3, 0],
[3, 2, 0],
[0, 2, 1],
[1, 1, 4],
[3, 2, 2],
[0, 1, 0],
[1, 3, 1],
[0, 4, 1],
[2, 4, 2],
[3, 3, 1]])
>>> idx = np.ran...
How to install pip with Python 3?
I want to install pip . It should support Python 3, but it requires setuptools, which is available only for Python 2.
21 A...
Why does SIGPIPE exist?
...|
edited Oct 26 '16 at 9:13
Ton van den Heuvel
8,39155 gold badges3434 silver badges7575 bronze badges
a...
Swapping column values in MySQL
...t. This method doesn't swap the values if one of them is NULL. Use method #3 that doesn't have this limitation.
UPDATE swap_test SET x=y, y=@temp WHERE (@temp:=x) IS NOT NULL;
This method was offered by Dipin in, yet again, the comments of http://beerpla.net/2009/02/17/swapping-column-values-in-mys...
Pandas get topmost n records within each group
...
3 Answers
3
Active
...
Find which version of package is installed with pip
...
As of pip 1.3, there is a pip show command.
$ pip show Jinja2
---
Name: Jinja2
Version: 2.7.3
Location: /path/to/virtualenv/lib/python2.7/site-packages
Requires: markupsafe
In older versions, pip freeze and grep should do the job nice...
How to get row from R data.frame
...
130
x[r,]
where r is the row you're interested in. Try this, for example:
#Add your data
x <...