从csv文件读取并保存特定的列

Question

需要帮忙！ 通过使用先前的主题，我发现了如何读取csv文件中的数据的方法，对此我没有任何问题，但是我无法将特定的列（例如file.csv中的第4列）另存为new.csv文件。 我的脚本正确打印了第4列，但没有保存。

import csv

with open('file.csv') as csvfile:
    file1 = csv.reader(csvfile, delimiter=',')
    fourth_col = []

    for cols in file1:
        fourth_col = cols[3]
        print (fourth_col)

        new_file = open('new.csv', 'w')
        writer = csv.writer(new_file)
        writer.writerows(fourth_col)
        new_file.close()

Answer 1

我尝试了以下代码，它工作正常

import csv

new_file = open('new.csv', 'w')
writer = csv.writer(new_file)

with open('file.csv') as csvfile:
    file1 = csv.reader(csvfile, delimiter=',')
    fourth_col = []

for cols in file1:
    fourth_col = cols[3]
    print(fourth_col)
    writer.writerows(fourth_col)

new_file.flush()
new_file.close()

样本文件：

FILE.CSV

a,b,c,d,e
f,g,h,i,j
k,l,m,,n
,,,o,

new.csv

d
i
o