Python：將csv行中的所有值轉換爲編號

Question

我有單元格中帶有製表符分隔數字的csv文件。

我想將行中的所有值轉換爲數組中的數字。

例如： 輸入：

1 2 3 4 
0 1 1 3 

輸出：

[1234, 0113] 

怎麼辦呢？

Answer 1

你做不需要re，只是split，str.join並映射到int：

with open("in.txt") as f: 
    nums = map(int,("".join(x.rstrip().split()) for x in f)) 

使用或不使用map：

[int(s) for s in (x.rstrip().replace(" ","") for x in f)] 

的文件用100行：

In [49]: %%timeit 
with open("in.txt") as f: 
    nums = map(int,("".join(x.rstrip().split()) for x in f)) 
    ....: 
10000 loops, best of 3: 140 µs per loop 

In [50]: %%timeit 
with open('in.txt', 'r') as istr: 
    lines = [re.sub(r'\s*', '', line) for line in istr] 
    [int(n) for n in lines] 
    ....: 
1000 loops, best of 3: 519 µs per loop 

In [53]: %%timeit 
    ....: with open("in3.txt") as f: 
    ....:  nums = [int(s) for s in (x.rstrip().replace(" ","") for x in f)] 
    ....: 
10000 loops, best of 3: 127 µs per loop 

Answer 2

如果你想從每行刪除所有空格，你可以使用正則表達式：

import re 

lines = list() 
with open('input.txt', 'r') as istr: 
    for line in istr: 
     line = re.sub(r'\s*', '', line) 
     lines.append(line) 

或者，如果你喜歡它的功能：

import re 

with open('input.txt', 'r') as istr: 
    lines = [re.sub(r'\s*', '', line) for line in istr] 

注意上面的例子會給你一個字符串列表。如果你想將它們轉換爲整數，你可以將int內置函數映射到它。

numbers = [int(n) for n in lines]