python：使变量等于运算符（+，/，*， - ） [英] python: make a variable equal an operator (+,/,*,-)

问题描述

这是我现在得到的，只是一个示例（现在键入它，所以不要担心关于简单错误）

  if image ==lighten：
 red_channel = red_channel + 50 
 else ：// image is darken 
 red_channel = red_channel  -  50 
  

注意我是如何重复完全相同的代码，用不同的运算符。
可以实现这样的：

  if（image ==lighten）：
 operator = + 
 else：
 operator =  -  
 
 red_channel = red_channel operator 50 
  

解决方案

  import operator 
 if（image =='lighten'）：
 op = operator.add 
 else：
 op = operator.sub 
 
 red_channel = op（red_channel，50）
  

或者，如果您有一些可能的操作，

  op = {
'lighten'：operator.add，
'darken'：operator.sub，
 ... 
} 
 red_channel = op [image]（red_channel， 50）
  

is it possible to assign a variable a maths operator.

this is what I've currently got, just a sample (typed it in now, so dont worry about simple errors)

if image == "lighten":
    red_channel = red_channel + 50
else:  // image is darken
    red_channel = red_channel  - 50

notice how i am repeating the exact same code, with a different operator. Is it possible to achieve something like this:

if (image == "lighten"):
    operator = +
else:
    operator = - 

red_channel = red_channel operator 50

解决方案

import operator
if (image == 'lighten'):
    op = operator.add
else:
    op = operator.sub

red_channel = op(red_channel, 50)

Or, if you have a number of possible operations,

op = {
    'lighten':operator.add,
    'darken':operator.sub,
     ...
    }
red_channel = op[image](red_channel,50)

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