如何从命令行参数向csv文件添加新列（标题） [英] How to add new column(header) to a csv file from command line arguments

问题描述

以下代码的输出：

import datetime
import csv
file_name='sample.txt'
with open(file_name,'rb') as f:               
    reader = csv.reader(f,delimiter=",")                                              
    #headers = reader.next()
    p=[]
    for row in reader:

        row[0] = row[0].zfill(6) 
        row[2] = row[2].zfill(6)
        row[3] = row[3].zfill(6)
        row[4] = row[4].zfill(6)
        row[1] = row[1][5:7] + "-" + row[1][8:10] + "-" + row[1][:4]
        p.append(row[:5])
        print p
with open('names.txt', 'wb') as ofile:
    writer = csv.writer(ofile)
    for row in p:
        writer.writerow(row)

如下： -

User_ID,--Date,0Num_1,0Num_2,Com_ID
000101,04-13-2015,000012,000021,001011
000102,04-03-2014,000001,000007,001002
000103,06-05-2013,000003,000004,000034
000104,12-31-2012,000004,000009,001023
000105,09-09-2011,000009,000005,000104

我要为csv添加一个新列文件从命令行。
例如 python script_name.py Dept_ID位置会为Comp_ID旁边的Dept_ID和位置创建列。

I want to add a new column to the csv file from command line. e.g. python script_name.py Dept_ID Location will create columns for Dept_ID and Location next to Comp_ID.

任何人都可以在这里指导我！

Can any one guide me here please!

推荐答案

请参阅这篇文章< a>其中建议如下：

see this post which suggests something like the following:

header = ['User_ID','--Date','0Num_1','0Num_2','Com_ID']
writer = csv.DictWriter(outcsv, fieldnames = header)
writer.writeheader()
writer.writerows({col: row} for row, col in zip(header, p))

从系统参数解析额外的列use sys.argv

to parse the extra columns from the system arguments use sys.argv

import sys

extra_headers = sys.argv
header.extend(sys.argv)
n = len(sys.argv)

writer = csv.DictWriter(outcsv, fieldnames = header)
writer.writeheader()

col_fill = ''
# extend p with two columns of blank data
writer.writerows({col: row_item} for row in p for row_item,col in zip(row+[col_fill]*n,header))

这里我遍历每一行，然后创建一个字典，按顺序将数据分配给每一列。注意 [col_fill] * n 这会创建一个等于 col_fill 的相同项目的列表，

here I iterate through each row, I then crate a dictionary to allocate data to each column in order. Notice [col_fill]*n this creates a list of identical items equal to col_fill that will be used to fill the additional columns parsed in via command line arguments.

在此示例中，命令行参数将被解析为：

In this example the command line arguments would be parsed as:

$ python script_name.py Dept_ID Location

/ p>

and would create:

User_ID,--Date,0Num_1,0Num_2,Com_ID,Dept_ID,Location
000101,04-13-2015,000012,000021,001011,,
000102,04-03-2014,000001,000007,001002,,
000103,06-05-2013,000003,000004,000034,,
000104,12-31-2012,000004,000009,001023,,
000105,09-09-2011,000009,000005,000104,,

这篇关于如何从命令行参数向csv文件添加新列（标题）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！