I have a array=(4,2,8,9,1,0) and I don't want to sort the array to find the highest number in the array because I need to get the index value of the highest number as it is, so I can use it for further reference.
Expected output:
9 index value => 3
Can somebody help me to achieve this?
Slight variation with a loop using the ternary conditional operator and no assumptions about range of values:
arr=(4 2 8 9 1 0)
max=${arr[0]}
maxIdx=0
for ((i = 1; i < ${#arr[@]}; ++i)); do
maxIdx=$((arr[i] > max ? i : maxIdx))
max=$((arr[i] > max ? arr[i] : max))
done
printf '%s index => values %s\n' "$maxIdx" "$max"
The only assumption is that array indices are contiguous. If they aren't, it becomes a little more complex:
arr=([1]=4 [3]=2 [5]=8 [7]=9 [9]=1 [11]=0)
indices=("${!arr[@]}")
maxIdx=${indices[0]}
max=${arr[maxIdx]}
for i in "${indices[@]:1}"; do
((arr[i] <= max)) && continue
maxIdx=$i
max=${arr[i]}
done
printf '%s index => values %s\n' "$maxIdx" "$max"
This first gets the indices into a separate array and sets the initial maximum to the value corresponding to the first index; then, it iterates over the indices, skipping the first one (the :1 notation), checks if the current element is a new maximum, and if it is, stores the index and the maximum.
for i in ${!arr[@]}; do. The rest of your code takes a little tweaking to avoid the assumption that 0 is the smallest index.arr[i] <= max once, and continue the loop if true. Then you can unconditionally update maxIdx and max.
Without using sort, you can use a simple loop in shell. Here is a sample bash code:
#!/usr/bin/env bash
array=(4 2 8 9 1 0)
for i in "${!array[@]}"; do
[[ -z $max ]] || (( ${array[i]} > $max )) && { max="${array[i]}"; maxind=$i; }
done
echo "max=$max, maxind=$maxind"
max=9, maxind=3
arr=(4 2 8 9 1 0)
paste <(printf "%s\n" "${arr[@]}") <(seq 0 $((${#arr[@]} - 1)) ) |
sort -k1,1 |
tail -n1 |
sed 's/\t/ index value => /'
printfseqpastesorttail -n1sed. One could use ex. cut -d, -f2 to get only the index or use read a b <( ... ) to read the numbers into variables, etc.Using Perl
$ export data=4,2,8,9,1,0
$ echo $data | perl -ne ' map{$i++; if($_>$x) {$x=$_;$id=$i} } split(","); print "max=$x", " index=",--${id},"\n" '
max=9 index=3
$
