用于创建数组的Shell脚本

Question

I want for every number in a unix file run a grep with the exact content in a second file and put the results I find in an array.

The first file (words) is in this form:

a
b
c
d

and the second one (frequencies) contains

f 3
b 8
d 4
v 2
a 5
c 2

so I want to create arrays that contain the following:

[a 5]
[b 8]
[c 2]
[d 4]

help much appreciated!

Answer 1

You need to reset the IFS variable (the delimeter used for arrays).

OIFS=$IFS #save original
IFS=','
arr=($(awk 'FNR==NR {a[$1]=$2;next} a[$1] {print $1,a[$1]","}' second first))
IFS=$OIFS

echo ${arr[0]}
a 5
echo ${arr[1]}
b 8
echo ${arr[*]}
a 5
b 8
c 2
d 4

Answer 2

a solution using join could be:

sort second > second.sort
IFS=','
arr=($(join first second.sort | tr '\n' ','))
rm second.sort

output:

echo ${arr[0]}
a 5