how Store result of a command in an array and put "none" i the information is missing?

Question

Im using a function that gives me 300 000 lines that look like this :

XXXXXXXXX 
WWWWWWWWWWWW

ZZZZZZZZZZ

eeeeeeeeeee

and i want to get something like this in an array

tab[0]=XXXXXXXXX tab[1]= tab[1]= WWWWWWWWWWWW tab[1]= none

I tried this :

#!/bin/bash
for i in text.txt
do
   tab=[i]
done

Please take a look at [How do I format my posts using Markdown or HTML?](https://stackoverflow.com/help/formatting). — Cyrus, Jul 12 '22 at 16:28
Could you please also format your example data as it were code? Otherwise symbols could be misplaced or misinterpreted. — mashuptwice, Jul 12 '22 at 16:29
Does this answer your question? [Looping through the content of a file in Bash](https://stackoverflow.com/questions/1521462/looping-through-the-content-of-a-file-in-bash) — mashuptwice, Jul 12 '22 at 16:30
Why do you have 3 different values for `tab[1]`? Did you mean `tab[2]` and `tab[3]`? — Barmar, Jul 12 '22 at 16:39
I don't see how your desired result is related to the sample file. — Barmar, Jul 12 '22 at 16:40

score 0 · Accepted Answer · answered Jul 12 '22 at 16:43

Use a while read loop to read the file line by line, and append the line to the tab array.

tab=()
while read -r line; do
    tab+=("${line:-none}")
done < filename

:-default in a variable expansion means to use default if the variable is empty, so empty lines will be replaced with none in the array.

score 0 · Answer 2 · answered Jul 12 '22 at 17:35

0

Use mapfile to map lines of text to an array:

mapfile -t tab < text.txt

answered Jul 12 '22 at 17:35

Léa Gris

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ufopilot · Answer 3 · 2022-07-12T21:32:07.907

$ readarray -t tab <file
$ declare -p tab
declare -a tab=([0]="XXXXXXXXX " [1]="WWWWWWWWWWWW" [2]="" [3]="ZZZZZZZZZZ" [4]="" [5]="eeeeeeeeeee")

# adding none
$ readarray -t tab < <(awk '{print ($0=="" ? "none" : $0)}' file)
$ declare -p tab
declare -a tab=([0]="XXXXXXXXX" [1]="WWWWWWWWWWWW" [2]="none" [3]="ZZZZZZZZZZ" [4]="none" [5]="eeeeeeeeeee")

# associative array
$ declare -A arr="($(awk '{print ($0=="" ? "[tab,"NR"]=\"none\"" : "[tab,"NR"]=\""$0"\"")}' file))"
$ declare -p arr
declare -A arr=([tab,6]="eeeeeeeeeee" [tab,4]="ZZZZZZZZZZ" [tab,5]="none" [tab,2]="WWWWWWWWWWWW" [tab,3]="none" [tab,1]="XXXXXXXXX" )

how Store result of a command in an array and put "none" i the information is missing?

3 Answers3