Hcfyk

I have file.txt that I need to read into a Bash array. Then I need to remove spaces, double quotes and all but the first comma in every entry. Here's how far I've gotten:

$ cat file.txt
10,this
2 0 , i s
30,"all"
40,I
50,n,e,e,d,2
60",s e,e"

$ cat script.sh
#!/bin/bash
readarray -t ARRAY<$1
ARRAY=( "$ARRAY[@]// /" )
ARRAY=( "$ARRAY[@]//"/" )
for ELEMENT in "$ARRAY[@]";do
 echo "|ELEMENT|$ELEMENT|"
done

$ ./script.sh file.txt
|ELEMENT|10,this|
|ELEMENT|20,is|
|ELEMENT|30,all|
|ELEMENT|40,I|
|ELEMENT|50,n,e,e,d,2|
|ELEMENT|60,se,e|

Which works great except for the comma situation. I'm aware that there are multiple ways to skin this cat, but due to the larger script this is a part of, I'd really like to use parameter substitution to get to here:

|ELEMENT|10,this|
|ELEMENT|20,is|
|ELEMENT|30,all|
|ELEMENT|40,I|
|ELEMENT|50,need2|
|ELEMENT|60,see|

Is this possible via parameter substitution?

I would remove what you need to remove using sed before loading into the array (also note the lower case variable names, in general it is best to avoid capitalized variables in shell scripts):

#!/bin/bash
readarray -t array< <(sed 's/"//g; s/ *//g; s/,/"/; s/,//g; s/"/,/' "$1")
for element in "$array[@]";do
 echo "|ELEMENT|$element|"
done

This produces the following output on your example file:

$ foo.sh file 
|ELEMENT|10,this|
|ELEMENT|20,is|
|ELEMENT|30,all|
|ELEMENT|40,I|
|ELEMENT|50,need2|
|ELEMENT|60,see|

If you really must use parameter substitution, try something like this:

#!/bin/bash
readarray -t array< "$1"
array=( "$array[@]// /" )
array=( "$array[@]//"/" )
array=( "$array[@]/,/"" )
array=( "$array[@]//,/" )
array=( "$array[@]/"/," )

for element in "$array[@]"; do
 echo "|ELEMENT|$element|"
done

As far as I can see, there's no need to read it into a bash array to create that output:

$ sed 's/[ "]//g; s/,/ /; s/,//g; s/ /,/; s/.*/|ELEMENT|&|/' <file
|ELEMENT|10,this|
|ELEMENT|20,is|
|ELEMENT|30,all|
|ELEMENT|40,I|
|ELEMENT|50,need2|
|ELEMENT|60,see|

The sed expression deletes spaces and double quotes, replaces the first comma with a space (there are no other spaces in the string at this point), deletes all other commas, restores the first comma, and the prepends and appends the extra data.

Alternatively, with GNU sed:

sed 's/[ "]//g; s/,//2g; s/.*/|ELEMENT|&|/' <file

(standard sed does not support the combination of 2 and g as flags to the s command).

ELEMENT='50,n,e,e,d,2'
IFS=, read -r first rest <<<"$ELEMENT"
printf "%s,%sn" "$first" "$rest//,/"

50,need2

Get out of the habit of using ALLCAPS variable names. You'll eventually collide with a crucial "system" variable like PATH and break your code.

[This is essentially a more fully developed version of glenn jackmann's answer]

Building an associative array from the stripped key and value, using the first comma as separator:

declare -A arr
while IFS=, read -r k v; do arr["$k//[ "]"]="$v//[ ,"]"; done < file.txt
for k in "$!arr[@]"; do 
 printf '|ELEMENT|%s,%s|n' "$k" "$arr[$k]"
done
|ELEMENT|20,is|
|ELEMENT|10,this|
|ELEMENT|50,need2|
|ELEMENT|40,I|
|ELEMENT|60,see|
|ELEMENT|30,all|

You could loop over the array and use an intermediate variable:

for((i=0; i < "$#ARRAY[@]"; i++))
do
 rest="$ARRAY[i]#*,"
 ARRAY[i]="$ARRAY[i]%%,*","$rest//,/"
done

This assigns to rest the portion after the first comma; we then concatenate three pieces back into the original variable:

• the portion before the first comma


• a comma


• the replacement in rest of every comma with nothing