BASH - 如何从 CSV 文件的列中提取数据并将其放入数组中？
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BASH - How to extract data from a column in CSV file and put it in an array?
提问by DMS
I am learning to script in Bash.
我正在学习在 Bash 中编写脚本。
I have a CSV file with 5 columns and 22 rows. I am interested in taking the data from the second column and put it into an array.
我有一个包含 5 列和 22 行的 CSV 文件。我有兴趣从第二列中获取数据并将其放入数组中。
What I want is that the first name be in array[0], the second in array[1]and so on.
我想要的是第一个名字在array[0]，第二个在array[1]等等。
Bash script:
bash脚本：
#!/bin/sh
IFS=","
eCollection=( $(cut -d ',' -f2 MyAssignment.csv ) )
printf "%s\n" "${eCollection[0]}"
The CSV looks like this. There is no line with headers.
CSV 看起来像这样。没有标题行。
The column with the Vl18xxnumbers is what I want to split into an array.
带有Vl18xx数字的列是我想要拆分为数组的内容。
John,Vl1805,VRFname,10.9.48.64/28,10.9.48.78
John,Vl1806,VRFname,10.9.48.80/28,10.9.48.94
John,Vl1807,VRFname,10.9.48.96/28,10.9.48.110
John,Vl1808,VRFname,10.9.48.112/28,10.9.48.126
John,Vl1809,VRFname,167.107.152.32/28,167.107.152.46
The bash script is not placing the 2nd column into the array, what am I doing wrong?
bash 脚本没有将第二列放入数组中，我做错了什么？
回答by Adam Burry
Remove the IFS=","assignment thereby letting the default IFS value of space, tab, newline apply
删除IFS=","分配从而让空格、制表符、换行符的默认 IFS 值应用
#!/bin/bash
eCollection=( $(cut -d ',' -f2 MyAssignment.csv ) )
printf "%s\n" "${eCollection[0]}"
回答by konsolebox
Better is to use readarray. No need to mind about IFS which could have any value, and is safe from pathname expansion.
更好的是使用readarray. 无需担心 IFS 可能具有任何价值，并且不会受到路径名扩展的影响。
readarray -t eCollection < <(cut -d, -f2 MyAssignment.csv)
printf '%s\n' "${eCollection[0]}"
回答by Aleks-Daniel Jakimenko-A.
Two pure bash solutions:
两种纯 bash 解决方案：
eCollection=()
while IFS=',' read -r _ second _; do
eCollection+=("$second")
done < file.txt
printf '%s\n' "${eCollection[0]}"
readarray -t eCollection < file.txt
eCollection=("${eCollection[@]#*,}")
eCollection=("${eCollection[@]%%,*}")
printf '%s\n' "${eCollection[0]}"
回答by Md Shihab Uddin
i like to use awk. First split based on ,delimiter and take required column values into array.
我喜欢用awk。首先根据,分隔符拆分并将所需的列值放入数组。
abc=($(tail -n +1 MyAssignment.csv | awk -F ',' '{print ;}'))
echo ${abc[1]}
Index start from 1. If the file contains headers, replace +1with +2to ignore headers.
指数从1开始。如果文件中包含头文件，替代+1与+2忽略标题。
