大约有 47,000 项符合查询结果（耗时：0.0725秒） [XML]
PHP: merge two arrays while keeping keys instead of reindexing?
...
You can simply 'add' the arrays:
>> $a = array(1, 2, 3);
array (
0 => 1,
1 => 2,
2 => 3,
)
>> $b = array("a" => 1, "b" => 2, "c" => 3)
array (
'a' => 1,
'b' => 2,
'c' => 3,
)
>> $a + $b
array (
0 => 1,
1 => 2,
2 ...
What is the significance of initializing direction arrays below with given values when developing ch
...what move each index of the arrays will make from the central point, X, at 2,2.)
.....
.536.
.1X0.
.724.
.....
The way it is set up, if you do ^1 (^ being bitwise XOR) on the index you get the opposite direction - 0 and 1 are opposites, 2 and 3 are opposites and so on. (Another way to set it up i...
Pandas DataFrame column to list [duplicate]
...
270
You can use the Series.to_list method.
For example:
import pandas as pd
df = pd.DataFrame({...
How to remove specific elements in a numpy array
...index)
For your specific question:
import numpy as np
a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9])
index = [2, 3, 6]
new_a = np.delete(a, index)
print(new_a) #Prints `[1, 2, 5, 6, 8, 9]`
Note that numpy.delete() returns a new array since array scalars are immutable, similar to strings in Python...
Difference between '..' (double-dot) and '…' (triple-dot) in range generation?
...
|
edited Dec 21 '16 at 0:33
answered Mar 13 '12 at 19:48
...
LINGO使用指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...求解如下的LP问题：
在模型窗口中输入如下代码：
min=2*x1+3*x2;
x1+x2>=350;
x1>=100;
2*x1+x2<=600;
然后点击工具条上的按钮 即可。
例1.2 使用LINGO软件计算6个发点8个收点的最小费用运输问题。产销单位运价如下表。
...
Append column to pandas dataframe
...ust looking for a join:
> dat1 = pd.DataFrame({'dat1': [9,5]})
> dat2 = pd.DataFrame({'dat2': [7,6]})
> dat1.join(dat2)
dat1 dat2
0 9 7
1 5 6
share
|
improve this answ...
What is the easiest way to push an element to the beginning of the array?
...elf, moving other elements upwards.
And in use:
irb>> a = [ 0, 1, 2]
=> [0, 1, 2]
irb>> a.unshift('x')
=> ["x", 0, 1, 2]
irb>> a.inspect
=> "["x", 0, 1, 2]"
share
|
im...
How do write IF ELSE statement in a MySQL query
...ably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case when (action = 2 and state = 0)
THEN
1
ELSE
0
END)
as state from tbl1;
share
|
improve this an...
Convert a row of a data frame to vector
...
answered Jan 23 '13 at 16:42
Ben BolkerBen Bolker
160k1919 gold badges286286 silver badges366366 bronze badges
...