数据结构 - python-如何把元素为字符串的二维列表转化为元素为整型的二维列表？

Question

我有一个二维列表：

li = [['1','2'],['3','4']]

如何把元素化为整型？
要处理的数据量很大，遍历li是否会降低效率，有其他的方法吗？

Answer 1

Traverse, since every number needs to be converted, in theory the conversion program must visit each element at least once

Answer 2

Same idea as above, use map

map(lambda x:map(int, x), li)

Answer 3

Use list parsing, but still need to traverse.
As mentioned above, because every element is accessed and then converted, let’s traverse it. . .

Answer 4

If the values ​​are used in scattered places, convert each time a value is used and replace the original value.

Answer 5

One line of code to get it done: li_int = [map(int, e) for e in li]

The complexity of the conversion is linear and can be tolerated if the amount of data is not particularly large. If there is really a lot of data, whichever one is used will be used for conversion.