迭代二维python列表

问题描述

我创建了一个二维数组，如:

rows =3列= 2mylist = [[0 for x in range(columns)] for x in range(rows)]对于范围(行)中的 i:对于范围(列)中的 j:mylist[i][j] = '%s,%s'%(i,j)打印我的列表

打印这个列表给出一个输出:

[ ['0,0', '0,1'], ['1,0', '1,1'], ['2,0', '2,1'] ]

其中每个列表项都是一个格式为'row,column'的字符串

现在给出这个列表，我想按顺序遍历它:

'0,0''1,0''2,0''0,1''1,1''2,1'

即迭代第一列然后第二列等等.我如何用循环来做到这一点?

这个问题属于纯 python 列表，而标记为相同的问题属于 numpy 数组.它们明显不同

解决方案

使用 zip 和 itertools.chain.类似的东西:

>>>从 itertools 导入链>>>l = chain.from_iterable(zip(*l))<itertools.chain 对象在 0x104612610>>>>列表(l)['0,0', '1,0', '2,0', '0,1', '1,1', '2,1']

I have created a 2 dimension array like:

rows =3
columns= 2
mylist = [[0 for x in range(columns)] for x in range(rows)]
for i in range(rows):
    for j in range(columns):
        mylist[i][j] = '%s,%s'%(i,j)
print mylist

Printing this list gives an output:

[  ['0,0', '0,1'], ['1,0', '1,1'], ['2,0', '2,1']   ]

where each list item is a string of the format 'row,column'

Now given this list, i want to iterate through it in the order:

'0,0'
'1,0'
'2,0'
'0,1'
'1,1'
'2,1'

that is iterate through 1st column then 2nd column and so on. How do i do it with a loop ?

This Question pertains to pure python list while the question which is marked as same pertains to numpy arrays. They are clearly different

解决方案

Use zip and itertools.chain. Something like:

>>> from itertools import chain
>>> l = chain.from_iterable(zip(*l))
<itertools.chain object at 0x104612610>
>>> list(l)
['0,0', '1,0', '2,0', '0,1', '1,1', '2,1']

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