Question

我正在研究一些代码，以从输入的.txt文件生成两个新的CSV文件。 .txt文件具有40列数据，我正在编写两个新的csv文件，每个文件仅从.txt文件中占据2列。

我的代码运行良好，几乎可以满足我的需求。最后一步是在两个新的csv输出中重命名原始标头。

这是我的代码：

import csv

QATargetHeaders = ['FNAME','LNAME']
FinalTargetHeaders = ['PROJECT_CODE','PHONE_NUMBER']

with open('TEST.txt','r') as csv_input, open('Test_QA2.csv','w') as csv_output:
    reader = csv.DictReader(csv_input, delimiter='^')
    writer = csv.DictWriter(csv_output, fieldnames=QATargetHeaders, extrasaction='ignore')
    writer.writeheader()
    for line in reader:
        writer.writerow(line)
with open('TEST.txt','r') as csv_input, open('Test_FINAL.csv','w') as csv_output:
    reader = csv.DictReader(csv_input, delimiter='^')
    writer = csv.DictWriter(csv_output, fieldnames=FinalTargetHeaders, extrasaction='ignore')
    writer.writeheader()
    for line in reader:
        writer.writerow(line)

对于TEST_QA2.csv，我需要更改标题：

FNAME = First Name
LNAME = Last Name

对于TEST_FINAL.csv，我需要更改标题：

PROJECT_CODE = PROJECT ID
PHONE_NUMBER = DEVICE1

有人可以帮我弄清楚如何在这里重写标题吗？必须将TargetHeaders定义为.txt文件中的确切列名，以便我的作者知道要复制的内容。在此先谢谢您

Answer 1

line是dict。字典键用作标题。因此，在编写新的csv之前，您必须重命名密钥。您可以通过dict理解来做到这一点。

import csv

QATargetHeaders = ['First Name','Last Name']
FinalTargetHeaders = ['PROJECT ID','DEVICE1']

map_QATargetHeaders = (('FNAME', 'First Name'), ('LNAME', 'Last Name'))
map_FinalTargetHeaders = (('PROJECT_CODE', 'PROJECT ID'), ('PHONE_NUMBER', 'DEVICE1LNAME'))

with open('TEST.txt','r') as csv_input, open('Test_QA2.csv','w') as csv_output:
    reader = csv.DictReader(csv_input, delimiter='^')

    writer = csv.DictWriter(csv_output, fieldnames=QATargetHeaders, extrasaction='ignore')
    writer.writeheader()
    for line in reader:
        line = {map[1]:line[map[0]] for map in map_QATargetHeaders}
        writer.writerow(line)

with open('TEST.txt','r') as csv_input, open('Test_FINAL.csv','w') as csv_output:
    reader = csv.DictReader(csv_input, delimiter='^')

    writer = csv.DictWriter(csv_output, fieldnames=FinalTargetHeaders, extrasaction='ignore')
    writer.writeheader()
    for line in reader:
        line = {map[1]:line[map[0]] for map in map_FinalTargetHeaders}
        writer.writerow(line)

Answer 2

将writeheader与字典配合使用，而不是writerow，将旧标头映射到新标头。然后，您可以像以前一样写其他行。

QATargetHeaders = {'FNAME': 'First Name','LNAME': 'Last Name'}
FinalTargetHeaders = {'PROJECT_CODE': 'PROJECT ID','PHONE_NUMBER': 'DEVICE1'}
...
    writer = csv.DictWriter(csv_output, fieldnames=QATargetHeaders, extrasaction='ignore')
    writer.writerow(QATargetHeaders)  # instead of writeheader
    for line in reader:
        writer.writerow(line)
...

（从Python 3.7 dictionaries preserve order开始，因此这些列将以正确的顺序显示。如果使用的是Python的早期版本，则需要创建一个单独的字段名称列表，或者使用{{3} }，以确保列以正确的顺序出现在CSV文件中。）

使用DictWriter更改列标题

2 个答案: