Hi folks just started write code in bash but stuck in my own question in want to count a to alphabets repetation in string like

read -p 'enter the string' str # SUPPOSE STRING USER ENTER IS

input = AAASSSSFFRREEE

i wanna get output like= A3S4F2R2E3

what can i do i am trying with for condition and this program is making monkey out of me

CodePudding user response：

One solution could be to loop over the string and strip away the first characters while counting them.

Example:

#!/bin/bash

IFS='' read -rp 'enter the string: ' str

res=''
# loop while the string is not empty
while [[ -n $str ]]
do
    # get the first character
    ch=${str:0:1}
    # create a regex matching the start of the string,
    # on one or more of the first character
    regex="^($ch )"
    # perform the regex matching
    [[ "$str" =~ $regex ]]
    # the matching string
    match="${BASH_REMATCH[1]}"
    # concatenate the character   the count to the result
    res="$res$ch${#match}"
    # remove the matching characters from the string
    str=${str#"$match"}
done

# print the result
printf "%s\n" "$res"

Examples:

CodePudding user response：

Unsorted alphabet

$ string="AAASSSSFFRREEE" 
$ grep -o . <<<"$string"|uniq -c|awk '{printf "%s%d", $2,$1}'
A3S4F2R2E3
$ string="AAASSSSFFRREEEAAAAFFFFFEE"
A3S4F2R2E3A4F5E2

Sorted alphabet

$ string="AAASSSSFFRREEE" 
$ grep -o . <<<"$string"|sort|uniq -c|awk '{printf "%s%d", $2,$1}'
A3E3F2R2S4
$ string="AAASSSSFFRREEEAAAAFFFFFEE"
A7E5F7R2S4