python-csv只写某些字段名，而不是全部字段名

Question

我一定遗漏了什么，但我不明白。我有一个csv，它有1200个字段。我只对30岁感兴趣。你是怎么做到的？我可以读/写整个shebang，这还可以，但我真的想把30写出来。我有一份名单，我有点砍头。

我该如何翻译以下内容以使用DictWriter/Reader？

for file in glob.glob( os.path.join(raw_path, 'P12*.csv') ):
    fileReader = csv.reader(open(file, 'rb'))
    fileLength = len(file)
    fileGeom = file[fileLength-7:fileLength-4]
    table = TableValues[fileGeom]
    filename = file.split(os.sep)[-1]
    with open(out_path + filename, "w") as fileout:
        for line in fileReader:
            writer = csv.writer(fileout, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
            if 'ID' in line:
                outline = line.insert(0,"geometryTable")
            else:
                outline = line.insert(0,table) #"%s,%sn" % (line, table)
            writer.writerow(line)

Answer 1

下面是一个使用DictWriter只写出您关心的字段的示例。我将把移植工作留给你：

import csv
headers = ['a','b','d','g']
with open('in.csv','rb') as _in, open('out.csv','wb') as out:
    reader = csv.DictReader(_in)
    writer = csv.DictWriter(out,headers,extrasaction='ignore')
    writer.writeheader()
    for line in reader:
        writer.writerow(line)

in.csv

a,b,c,d,e,f,g,h
1,2,3,4,5,6,7,8
2,3,4,5,6,7,8,9

结果（out.csv）

a,b,d,g
1,2,4,7
2,3,5,8