Add value to array using Bash script

Question

I have written the following script ,

#!/bin/bash
My_File=Image.csv
Value=YES
cat "$My_File" | while IFS=, read first last
do
    echo "first='$first' last='$last'"
    if [ "$last" == "$Value" ];
       then
       echo Match_Found
       echo $first
       array+=("$first")
       echo $first is Added
    fi
done
echo (${#array[@]})

It dosenot add any value to the array , Could someone point out to the issue . The Input is as follow ,

FA_2015-01_666,NO
FA_2015-01_777,YES
FA_2015-01_888,NO
FA_2015-01_999,YES
FA_2015-01_555,YES

array+={"$first") what happens when you change the last ) to a } ? — Aserre
– Aserre, Commented Jul 10, 2015 at 9:46
array+=($first) - This gaives same result , 0 and so does this array+=("$first") — Ashesh Nair
– Ashesh Nair, Commented Jul 10, 2015 at 9:51
What i want to know is why it even runs with unmatched braces — 123
– 123, Commented Jul 10, 2015 at 9:52
Actually that was an error when i copied over the code - My mistake ,on checking the Terminal , it appears to be correct — Ashesh Nair
– Ashesh Nair, Commented Jul 10, 2015 at 9:53

123 · Accepted Answer · 2015-07-10 09:59:02Z

2

Redirect the file in, don't pipe from cat or the loop is run in a subshell and everything in it is lost when it ends.

#!/bin/bash
My_File="Image.csv"
Value=YES
while IFS=, read first last
do
    if [ "$last" == "$Value" ];
       then
       echo Match_Found
       echo $first
       array+=("$first")
       echo $first is Added
    fi
done < "$My_File"
echo "${#array[@]}"

answered Jul 10, 2015 at 9:59

123

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2 Comments

Ashesh Nair Over a year ago

This works perfect , i was not aware of the cons mentioned by you.Thanks a lot for quick debug

123 Over a year ago

@AsheshNair No Problem. Just remember any variables set in a pipeline are lost when it ends :)

EEVV · Accepted Answer · 2015-07-10 09:59:39Z

0

I haven't done some bash coding in some time, but it should be like this (The way i do it):

#our table to insert an item to
table=( )
tableLength=${#table[@]}

#inserting items
table[$tableLength]="foo"
#you have to refresh this variable everytime
tableLength=${#table[@]}
table[$tableLength]="bar"
#or you can do this without refreshing the length variable
table[${#table[@]}]="foobar"

I recommend you use:

table=()
table[${#table[@]}]="item!"

using # as the length, and table[@] to display all items, so it gets the length of the array and sets an item to the length of an array or table

answered Jul 10, 2015 at 9:59

EEVV

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11 Comments

EEVV Over a year ago

also tables and arrays are the same thing

123 Over a year ago

This is tangibly related to the question and doesn't provide and answer to what OP is actually asking.

EEVV Over a year ago

alright, what's the fun in coding if you just copy/paste the answers, this is the way i learned, so I thought it would help.

123 Over a year ago

Who's copy and pasted anything ? I think the fun is actually solving problems instead of posting slightly related, personal preferences for coding. I honestly don't understand what your answer is trying to achieve.

EEVV Over a year ago

Well if you have actually read the answer instead of downvoting, the comments are pretty clear to me, I'm no scientist but I think i know what #inserting items means.

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