Python帮助：从csv文件创建{str：list of str}的字典 [英] Python Help: Creating a dict of {str:list of str} from csv file

问题描述

我必须以以下格式创建表格： {str：list of str}

I have to create a table in the format: {str: list of str}

.csv文件使用以下代码，我得到：

Opening a .csv file using the following code, I get:

import csv
cr = csv.reader(open("name.csv","r"))
for row in cr:
    print(row)

b $ b

输出：

output:

['key1', 'key2', 'key3']
['value1', 'value2', 'value3']
['value4', 'value5', 'value6']

我基本上需要将其结构化为

I essentially need to structure this into the format

{'key1': ['value1', 'value4'], 'key2': ['value2', 'value5'], 'key3': ['value3', 'value6']}

我被卡住了;我只是想不出一种方法来为它工作任何数量的键和值

I'm stuck; I just can't think of a way to do this for it to work for any number of keys and values

推荐答案

使用 zip（）将行转成列，然后将它们转换为字典键和值：

Use zip() to turn rows into columns, then make those into dictionary keys and values:

import csv

with open("name.csv", newline='') as infh:
    cr = csv.reader(infh)
    columns = {r[0]: list(r[1:]) for r in zip(*cr)}

最后一行的快速演示：

>>> cr = [
...     ['key1', 'key2', 'key3'],
...     ['value1', 'value2', 'value3'],
...     ['value4', 'value5', 'value6'],
... ]
>>> {r[0]: list(r[1:]) for r in zip(*cr)}
{'key3': ['value3', 'value6'], 'key2': ['value2', 'value5'], 'key1': ['value1', 'value4']}

cr 代表 csv.reader（）对象。

zip（* iterable）获取迭代中的所有元素，并将其转换为矩阵;列成为行，因为每个嵌套值与位于相同位置的其他行的值配对。

zip(*iterable) takes all elements in an iterable and transforms it like a matrix; columns become rows as each nested value is paired up with values from the other rows at the same position:

>>> zip(*[[1, 2, 3], [4, 5, 6]])
[(1, 4), (2, 5), (3, 6)]

和字符解析 {key_expression：value_expression for iterates} 一个字典，其中在上面的代码中一列中的每个第一个元素成为键，其余的形成值。

and the dict comprehension {key_expression: value_expression for targets in iterable} produces a dictionary, where in the above code each first element in a column becomes the key, and the rest forms the value.

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