Question

我想使用拆分字符串方法将每行的信息提取到列表中。

Answer 1

使用分界线，它更好：

operator=()

Answer 2

我不知道你的文件是怎么回事，但我认为它是这样的：

Hopper, Grace 100 98 87 97
Knuth, Donald 82 87 92 81
Goldberg, Adele 94 96 90 91
Kernighan, Brian 89 74 89 77
Liskov, Barbara 87 97 81 85

我也不明白你想要输出什么，但我认为它是这样的：

[['Hopper,', 'Grace', '100', '98', '87', '97'], ['Knuth,', 'Donald', '82', '87', '92', '81'], ['Goldberg,', 'Adele', '94', '96', '90', '91'], ['Kernighan,', 'Brian', '89', '74', '89', '77'], ['Liskov,', 'Barbara', '87', '97', '81', '85']]

我开发了这个单行代码（对于python 3.6）：

with open('scores.txt', 'r') as file:
    print([[value for value in line.strip().replace(',','').split()] for line in file])

与：

相同

with open('scores.txt', 'r') as file:
    tmp = []
    for line in file:
        tmp.append(line.strip().replace(',','').split())
        # Also you can delete tmp = [] and replace the tmp.append(...) line to tmp = [var for var in line.strip().replace(',','').split()]
print(tmp)

<强>输出：

[['Hopper,', 'Grace', '100', '98', '87', '97'], ['Knuth,', 'Donald', '82', '87', '92', '81'], ['Goldberg,', 'Adele', '94', '96', '90', '91'], ['Kernighan,', 'Brian', '89', '74', '89', '77'], ['Liskov,', 'Barbara', '87', '97', '81', '85']]

与：

相同

[
    ['Hopper,', 'Grace', '100', '98', '87', '97'],
    ['Knuth,', 'Donald', '82', '87', '92', '81'],
    ['Goldberg,', 'Adele', '94', '96', '90', '91'],
    ['Kernighan,', 'Brian', '89', '74', '89', '77'],
    ['Liskov,', 'Barbara', '87', '97', '81', '85']
]

我使用了like和输出print()，但你可以定义一个你想要的变量。

PD：我找到了一个更简单的解决方案：

with open('scores.txt', 'r') as file:
    print([line.split() for line in file.read().replace(',','').splitlines()])

Answer 3

假设您有以下字符串，其中包含单词（由水平空格分隔）和行（由\n或垂直空格分隔）：

>>> print(data)
Hopper, Grace 100 98 87 97
Knuth, Donald 82 87 92 81
Goldberg, Adele 94 96 90 91
Kernighan, Brian 89 74 89 77
Liskov, Barbara 87 97 81 85

如果您只是使用.split()，则会忽略行和单词之间的所有差异：

>>> data.split()
['Hopper,', 'Grace', '100', '98', '87', '97', 'Knuth,', 'Donald', '82', '87', '92', '81', 'Goldberg,', 'Adele', '94', '96', '90', '91', 'Kernighan,', 'Brian', '89', '74', '89', '77', 'Liskov,', 'Barbara', '87', '97', '81', '85']

要保持差异，您需要将.splitlines()与.split()合并：

>>> [line.split() for line in data.splitlines()]
[['Hopper,', 'Grace', '100', '98', '87', '97'], ['Knuth,', 'Donald', '82', '87', '92', '81'], ['Goldberg,', 'Adele', '94', '96', '90', '91'], ['Kernighan,', 'Brian', '89', '74', '89', '77'], ['Liskov,', 'Barbara', '87', '97', '81', '85']]

同样的概念适用于从文件读取的数据。您可以使用.splitlines()循环遍历文件的各行，而不是使用for：

>>> with open('/tmp/file.txt') as f:
...    for line in f:
...       print(line.split())
... 
['Hopper,', 'Grace', '100', '98', '87', '97']
['Knuth,', 'Donald', '82', '87', '92', '81']
['Goldberg,', 'Adele', '94', '96', '90', '91']
['Kernighan,', 'Brian', '89', '74', '89', '77']
['Liskov,', 'Barbara', '87', '97', '81', '85']

或者，如果您想要嵌套列表：

>>> with open('/tmp/file.txt') as f:
...    print([line.split() for line in f])
... 
[['Hopper,', 'Grace', '100', '98', '87', '97'], ['Knuth,', 'Donald', '82', '87', '92', '81'], ['Goldberg,', 'Adele', '94', '96', '90', '91'], ['Kernighan,', 'Brian', '89', '74', '89', '77'], ['Liskov,', 'Barbara', '87', '97', '81', '85']]

如果你只需要这些行中的一个数字：

>>> with open('/tmp/file.txt') as f:
...    print([line.split()[2] for line in f])
... 
['100', '82', '94', '89', '87']

打开文件并使用for循环或列表理解循环遍历的形式被认为是一种重要的Python习语。使用它们而不是将整个文件读入内存。

Answer 4

不要先将整个文件读入内存。文件对象是迭代器。

result = []
with open('scores.txt') as f:
    for line in f:
         # E.g., fields == ['Hopper,', 'Grace', '100', '98', '87', '97']
        fields = line.strip().split()

目前尚不清楚你想要什么作为最终结果;也许是每一行的一年级？拆分线后，您可以使用

result.append(fields[2])

读取文件 - python？

4 个答案: