Python - 以非线性方式运行循环

Question

SO, I am searching for a way to loop through a list of items in a for loop fashion, except I want the loop to iterate in a 'random' way. ie I dont want the loop to go 0,1,2,3,m+1...n, I want it to pick it in some random order and still run through the loop for all items.

Here is my current looping code:

for singleSelectedItem in listOfItems:
  item = singleSelectedItem.databaseitem
  logging.info(str(item))    

please let me know if this doesnt make sense ;)

Answer 1

If listOfItems can be shuffled, then

import random
random.shuffle(listOfItems)
for singleSelectedItem in listOfItems:
    blahblah

otherwise

import random
randomRange = range(len(listOfItems))
random.shuffle(randomRange)
for i in randomRange:
    singleSelectedItem = listOfItems[i]
    blahblah

Edit for Jochen Ritzel's better approach in the comment.
The otherwise part can be

import random
for item in random.sample(listOfItems, len(listOfItems))
    blahblah

Answer 2

import random
random.shuffle(listOfItems)

for singleSelectedItem in listOfItems:
  item = singleSelectedItem.databaseitem
  logging.info(str(item))

Answer 3

好吧，如果性能不是很重要，你可以随便洗牌，或者如果那些必须保持相同的顺序，创建一个所有indizes和shuffle的列表（例如indizes = range（len（listOfItems）），random.shuffle（ indizes））

Answer 4

>>> lst = ['a', 'b', 'c', 'd']
>>> nums = list(range(0, len(lst)))
>>> import random
>>> random.shuffle(nums)
>>> for i in nums:
...     print lst[i]
c
a
b
d

Or if the list is really large you can use a bit of generator flavoring. :-)