Python-如何使用列标题从CSV数据文件创建字典 [英] Python - How to Create Dictionary from CSV data file using column headings

问题描述

我正在尝试创建一个函数，该函数接受.csv数据文件的名称和表示该文件中列标题的字符串列表，并返回一个dict对象，每个键为列标题，而对应的值为numpy数据文件该列中的值的数组.

I am trying to create a function that accepts the name of a .csv data file and a list of strings representing column headings in that file and return a dict object with each key being a column heading and the corresponding value being a numpy array of the values in that column of the data file.

我现在的代码:

def columndata(filename, columns):
d = dict()
for col in columns:
with open(filename) as filein:
    reader = csv.reader(filein)
        for row in reader:
           if col in row:
               d.append(row)
return d

示例CSV如下:

test1,test2
3,2
1,5
6,47
1,4

columns文件如下:

The columns file looks like:

cols = ['test1', 'test2']

最终结果应该是这样的字典:

The end result should be a dictionary like this:

{'test1':[3,1,6,1], 'test2':[2, 5, 4, 4]}

推荐答案

您可以使用 DictReader ，它将CSV数据解析为字典:

You can use a DictReader which parse the CSV data into a dict:

import csv
from collections import defaultdict


def parse_csv_by_field(filename, fieldnames):
    d = defaultdict(list)
    with open(filename, newline='') as csvfile:
        reader = csv.DictReader(csvfile, fieldnames)
        next(reader)  # remove header
        for row in reader:
            for field in fieldnames:
                d[field].append(float(row[field]))  # thanks to Paulo!
    return dict(d)

print(parse_csv_by_field('a.csv', fieldnames=['cattle', 'cost']))

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