How to count number of values in a row and store total count to array

Question

I have a scenario where i want to get count of all values row by row and store it to dynamic array

Data in file :

"A","B","C","B"
"P","W","R","S"
"E","U","C","S"
"Y","F","C"

first row as : 4 -> values

second row as : 4 -> values

third row as : 4 -> values

fourth row as : 3 -> values

Expected Output : store to array : array_list=(4,4,4,3)

written a script but not working

array_list=()

while read -r line 
do 
    var_comma_count=`echo "$line" | tr -cd , | wc -c`
    array_list=+($( var_comma_count))
done < demo.txt

when i print array it should give me all values : echo "{array_list[@]}"

Note : The file might contain empty lines at last which should not be read

when i count file it gave me count : 5 , it should have ignored last line which is empty

where as when i use awk it give me proper count : awk '{print NF}' demo.txt -> 4

I know processing file using while loop is not a best practise , but any better solution will be appreciated

array_list=($(awk '{print NF}' demo.txt))? store it to dynamic array it's just an "array", it's not called "dynamic" I mean. — KamilCuk
– KamilCuk, Commented Jun 6, 2021 at 10:40
Also, you've been told before that you should copy/paste your scripts into shellcheck.net before asking questions about them, please do that and then edit your question to replace your current script with the fixed result. — Ed Morton
– Ed Morton, Commented Jun 6, 2021 at 12:04
@EdMorton Sure next time will check code with shell check and post question — codeholic24
– codeholic24, Commented Jun 6, 2021 at 12:07
No need to wait for next time, you can do it right now this time, it'll take you about 2 minutes at most. — Ed Morton
– Ed Morton, Commented Jun 6, 2021 at 12:09

The fourth bird · Accepted Answer · 2021-06-06 13:13:28Z

2

Perhaps this might be easier using awk, set the FS to a comma and check if the number of fields is larger than 0:

#!/bin/bash

array_list=($(awk -v FS=, 'NF>0 {print NF}' demo.txt))
echo "${array_list[@]}"

Output

4 4 4 3

The awk command explained:

awk -v FS=, '    # Start awk, set the Field Separator (FS) to a comma
NF>0 {print NF}  # If the Number of Fields (NF) is greater than 0, print the NF
' demo.txt       # Close awk and set demo.txt as the input file

Another option could be first matching the format of the whole line. If it matches, there is at least a single occurrence.

Then split the line on a comma.

array_list=($(awk '/^"[A-Z]"(,"[A-Z]")*$/{print(split($0,a,","));}' demo.txt))
echo "${array_list[@]}"

Output

4 4 4 3

The awk command explained:

awk '/^"[A-Z]"(,"[A-Z]")*$/{   # Regex pattern for the whole line, match a single char A-Z between " and optionally repeat preceded by a comma
  print(split($0,a,","));      # Split the whole line `$0` on a comma and print the number of parts
}
' demo.txt

edited Jun 6, 2021 at 13:13

answered Jun 6, 2021 at 11:45

The fourth bird

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3 Comments

codeholic24 Over a year ago

can you explain the code in detail will be helpful for others too

codeholic24 Over a year ago

is it possible to use this @ instead of '*' in array_list [ * ]

The fourth bird Over a year ago

@codeholic24 Yes, I have updated the answer.

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