列数未知的csv文件的Bash处理 [英] Bash processing of csv file with unknown number of columns

问题描述

我正在尝试使用bash学习一些文本处理.

I am trying to learn some text processing using bash.

如何制作bash脚本以读取和处理具有第一行作为列标题的未知列数的CSV文件?

How to make a bash script to read and process CSV file with unknown number of columns with first row as column headers?

示例输入:

column1,column2,...,columnn
value11,value12,...,value1n
value21,value22,...,value2n
...
valuem1,valuem2,...,valuemn

输出:

column1: value11
column2: value12
...
columnn: value1n

column1: value21
column2: value22
...
columnn: value2n

...

column1: valuem1
column2: valuem2
...
columnn: valuemn

推荐答案

一种简单的方法是设置 IFS =，并使用 read -a 读入数组:

One simple approach is to set IFS=, and use read -a to read into an array:

#!/bin/bash
IFS=','
read -a headers
while read -a line; do
    for i in "${!line[@]}"; do
        echo "${headers[i]}: ${line[i]}"
    done
done

发生的情况是，第一行被读取到一维数组 $ line 中，并根据 $ IFS 中的字符进行了拆分.在有可用输入的情况下，以相同的方式读取后续行，并且"$ {！line [@]}" 中的！指示bash循环遍历数组索引数组值.

What happens is that the first line is read into the one-dimensional array $line, being split according to the character in $IFS. Subsequent lines are read in the same way while there is input available, and the ! in "${!line[@]}" instructs bash to loop over array indices instead of array values.

如果数据使用任何形式的转义方法来包含逗号文字，则此方法将无效.

This will not work if the data use any sort of escaping method to include comma literals.

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