Python复制每一行，然后在每一行中进行更改答案

【问题标题】：Python replicate each line and then make change in each linePython复制每一行，然后在每一行中进行更改
【发布时间】：2017-08-07 22:15:22
【问题描述】：

我有一个 csv 文件，其中包含如下行：

0.10089,0,0,1,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0 0.10955,0,0,2,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0

我想将每一行复制3次，然后将每行中的第4个元素更改为(1,2,...)，以便所有行（包括复制的行）都成为此订单的一部分

0.10089,0,0,1,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0 0.10089,0,0,2,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0 0.10089,0,0,3,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0 0.10955,0,0,4,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0 0.10955,0,0,5,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0 0.10955,0,0,6,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0

我知道每个逗号的索引，因此知道第 4 个元素的位置

with fileinput.input(inplace=True) as f: for line in f: line = line.rstrip('\n') comma_pos_array = [i for i,x in enumerate(line) if x == ','] for i in range(3): print(line)

我尝试过一些方法，比如从0 to (number of lines in f)*3 创建一个连续整数数组，然后用这个新数组中的相应元素更改第 4 个元素，但它们似乎不起作用。

任何帮助将不胜感激！

【问题讨论】：

标签： python-3.5

【解决方案1】：

这将产生你想要的（没有 csv 模块）：

n = 1 # counter

for line in f:
    numbers = line.split(sep=',') # getting list of separated numbers
    for i in range(3):
        numbers[3] = n # replacing with proper value
        n += 1
        s = ''
        for i in numbers: # adding commas
            s += str(i) + ','
        s.rstrip(',') # removing last comma
        print(s)

【讨论】：

【解决方案2】：

这是使用csv module 读写输入/输出的变体：

from io import StringIO
from csv import reader, writer

txt = '''0.10089,0,0,1,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0
0.10955,0,0,2,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0'''

REPEAT = 3

with StringIO(txt) as infile, StringIO() as outfile:

    rows = reader(infile)
    out_csv = writer(outfile)

    counter = 0

    for row in rows:
        for i in range(REPEAT):
            counter += 1
            row[3] = counter
            out_csv.writerow(row)

    print(outfile.getvalue())

并产生输出：

0.10089,0,0,1,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0
0.10089,0,0,2,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0
0.10089,0,0,3,0,0,0,0,0,0,-1.8,-0.7,1999998.0,0,0,0,80,81.226,158.25,0
0.10955,0,0,4,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0
0.10955,0,0,5,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0
0.10955,0,0,6,0,0,0,0,0,0,-1.5,0.4,-4.1,0,0,0,88.127,87.784,158.47,0

（您需要将StringIO 部分替换为您的文件；我在这里使用它们来使示例独立）

【讨论】：