使用 DictReader 读取 csv 时不打印一行答案

【问题标题】：A row is not printed while using the DictReader to read a csv使用 DictReader 读取 csv 时不打印一行
【发布时间】：2022-01-23 21:44:39
【问题描述】：

我创建了一个 csv 文件，如下所示：

%%writefile employee2.csv
name, department, birthday month
John Smith, Accounting, November, 6
Erica Meyers, IT, March

现在我想用 DictRead 读取 csv 文件的每一行，但它不读取第二行 (John Smith)

import csv
with open('employee2.csv', newline='') as csv_file:
    csv_reader = csv.DictReader(csv_file, restkey='day', skipinitialspace=True)
    line_count = 0
    for row in csv_reader:
        if line_count == 0:
            print(f'Column names are: {", ".join(row)}')
        else:
            print(f'{row["name"]} works in the {row["department"]} department, and was born in {row["birthday month"]}.')
        line_count += 1

输出是：

Column names are: name, department, birthday month, day
Erica Meyers works in the IT department, and was born in March.

现在，我有两个问题： 1-为什么它不读取文件的第二行并打印出来？ 2- 如果我想在打印命令中添加restkey，我该怎么做？

最好的问候，

【问题讨论】：

标签： python csv

【解决方案1】：

当使用csv.DictReader时，它会在你开始逐行读取文件之前独立读取fieldnames，(for row in csv_reader:)。无需查看您是否正在阅读第一行（fieldnames）。

要将restkey 添加到打印中，pop 将其从行字典中删除，然后打印弹出的值。见this。

import csv
with open('tmp1.csv', newline='') as csv_file:
    csv_reader = csv.DictReader(csv_file, restkey='day', skipinitialspace=True)
    cols = csv_reader.fieldnames
    print('Column names are: ', cols)
    for row in csv_reader:
        day = row.pop('day', None)
        if day != None:
            print(f'{row["name"]} works in the {row["department"]} department, and was born on {row["birthday month"]} {day[0]}.')
        else:
            print(f'{row["name"]} works in the {row["department"]} department, and was born in {row["birthday month"]}.')

打印：

Column names are:  ['name', 'department', 'birthday month']
John Smith works in the Accounting department, and was born on November 6.
Erica Meyers works in the IT department, and was born in March.

【讨论】：

非常感谢您的解释。