bash check if value exist in array , it seems single(i) is trying to match with double digit numeric (10 is one of of the value in array)

Question

it seems single(i) is trying to match with double digit numeric (10 is one of of the value in array)

STATE 1

abc@xyz $ i=1
abc@xyz $ allStatus=(2 3 4 5 6 7 8 9 10)


abc@xyz $ if [[ ! ${allStatus[@]} =~ $i ]]
> then
> echo OK
> fi

STATE 2


abc@xyz $ i=2
abc@xyz $ allStatus=(1 3 4 5 6 7 8 9 10)
abc@xyz $  
abc@xyz $ if [[ ! ${allStatus[@]} =~ $i ]]
> then
> echo OK
> fi
OK
abc@xyz $

all i want is, STATE 1 should echo/print OK

@glennjackman not really a duplicate since here he can use a sparse array index and only do a single test and not search the whole array. — Léa Gris, Oct 25 '21 at 16:38

score 1 · Accepted Answer · answered Oct 25 '21 at 15:32

That's because the value after =~ is interpreted as a regular expression, and the string 10 matches the regular expression 1.

You need to check that there's a space or string start before the value and space or string end after the value:

[[ ${arr[@]} =~ ( |^)$i( |$) ]]

This can still fail if the value a 1 b belongs to the array:

foStatus=(2 3 'a 1 b')

The correct way is to iterate over the values and check for equality:

arr=(2 3 1 4 9 10 'a 1 b')
i=1
for v in "${arr[@]}" ; do
   if [[ $v == "$i" ]] ; then
       echo OK
   fi
done

Léa Gris · Answer 2 · 2021-10-25T17:06:58.100

Since you are checking a numeric status exist, you can use a sparse array index and do:

#!/usr/bin/env bash

i=2
allStatus=([1]=1 [3]=1 [4]=1 [5]=1 [6]=1 [7]=1 [8]=1 [9]=1 [10]=1)

if ((allStatus[i])); then
  echo OK
fi

You can also create a bit-field and check bit is on:

#!/usr/bin/env bash

i=2
allStatus=(1 3 4 5 6 7 8 9 10)
# Set all bits corresponding to status by expanding array elements
# into the arithmetic expression:
# 0 | 1 << element1 | 1 << element2 |...
allStatusBin=$((0${allStatus[@]/#/|1<<}))

# Or set it directly in binary
#allStatusBin=$((2#11111111010))

if ((1<<i&allStatusBin)); then
  echo OK
fi

bash check if value exist in array , it seems single(i) is trying to match with double digit numeric (10 is one of of the value in array)

2 Answers2