Question

我想替换我的csv文件的第一行。 csv文件由打开其他csv文件并读取某些列的脚本生成。它看起来像

TimeStamp;Value;Value; ...
2014/08/04 21:00:53.575;0.168889;1.146; ...
2014/08/04 21:01:23.590;0.168889;1.138; ...
2014/08/04 21:01:53.595;0.17;1.154; ...
2014/08/04 21:02:23.585;0.168889;1.205; ...

我想替换第一行（Timestamp; Value; Value），并将名称保存在列表中。

我想要的输出应该是

TimeStampfromlist;Firstnamefromlist;Secondnamefromlist; ...
2014/08/04 21:00:53.575;0.168889;1.146; ...
2014/08/04 21:01:23.590;0.168889;1.138; ...
2014/08/04 21:01:53.595;0.17;1.154; ...
2014/08/04 21:02:23.585;0.168889;1.205; ...

我该怎么做？

尝试更具体这是我用来生成csv文件的代码

import csv
import glob
import os, sys

path = "C:/Users/ButoeruG/Desktop/pythonscripts/prova"
dirs = glob.glob('*.csv')
namelist = dirs

print dirs[0]

file1 = dirs[1]
print file1
for file in namelist:
    namelist = file.partition("TrendLogExtended_")[2].partition("-Ext).csv")[0]
    print namelist


primofile = csv.reader(open(file1, 'rb'), delimiter=";", quotechar='|')
output_rows = []

for row in primofile:
    output_rows.append([row[2], row[15]])

for file in dirs:
    data = csv.reader(open(file, 'rb'), delimiter=";", quotechar='|')
    column = []
    for idx,row in enumerate(data):
        output_rows[idx].append(row[15])

with open("provaoutput.csv", 'wb') as f:
    writer = csv.writer(f, delimiter=';')
    for row in output_rows:
        writer.writerow(row)

现在重点是，当我写行[15]时，我只是从文件中复制一个看起来像这样的列：

Value;
1,956;
1;054;
1,456;

我想用我在名单中保存的部分文件名替换值。

Answer 1

您可以使用csv模块，但此逻辑可以满足您的需求。

l = ["TimeStampfromlist","Firstnamefromlist","Secondnamefromlist"]

with open("in.csv", 'r') as data_file:
    lines = data_file.readlines()
    lines[0]= ":".join(l)+"\n" # replace first line, the "header" with list contents
    with open("in.csv", 'w') as out_data:
        for line in lines: # write updated lines
            out_data.write(line)

Answer 2

一般方法是打开文件进行读取，跳过旧标题行，打开目标文件进行写入，写入新标题行，然后复制文件的其余部分。最后将新文件重命名为旧文件。

import os

new_headers = ['TimeStampfromlist', 'Firstnamefromlist', 'Secondnamefromlist']
filename = 'data.csv'
with open(filename, 'r') as lines:
    next(lines)  # Skip first line.
    tmp_filename = filename + '.tmp'
    with open(tmp_filename, 'w') as out_file:
        out_file.write(':'.join(new_headers) + '\n')
        out_file.writelines(lines)
    os.rename(tmp_filename, filename)

用list替换Python中的第一行

2 个答案: