Question

只是一个普通的.csv文件第一行有每列的标题。

我想知道如何创建一个新的.csv文件，该文件具有相同的标题（第一行），但包含原始文件的每5行？

谢谢你！

Answer 1

这将一次读取一行文件，只写行5,10,15,20 ......

import csv

count = 0

# open files and handle headers
with open('input.csv') as infile:
    with open('ouput.csv', 'w') as outfile:
        reader = csv.DictReader(infile)
        writer = csv.DictWriter(outfile, fieldnames=reader.fieldnames)
        writer.writeheader()

        # iterate through file and write only every 5th row
        for row in reader:
            count += 1
            if not count % 5:
                writer.writerow(row)

（使用Python 2和3）

如果您更愿意从数据行＃1开始写入第1,6,11,16行...在顶部更改为：

count = -1

Answer 2

这将采用任何文本文件，然后输出第一行和第5行。如果没有访问列，则不必将其作为.csv进行操作：

with open('a.txt') as f:
    with open('b.txt','w') as out:
        for i,line in enumerate(f):
            if i % 5 == 0:
                out.write(line)

Answer 3

如果你想使用csv库，那么更严格的版本就是......

import csv

# open files and handle headers
with open('input.csv') as infile:
    with open('ouput.csv', 'w') as outfile:
        reader = csv.DictReader(infile)
        writer = csv.DictWriter(outfile, fieldnames=reader.fieldnames)
        writer.writeheader()

        # iterate through file and write only every 5th row
        writer.writerows([x for i,x in enumerate(reader) if i % 5 == 4])

如何使用python选择.csv文件中的每第5行

3 个答案: