Only remove commas embedded within quotes in a comma delimited file

Question

I have a input file delimited with commas (,). There are some fields enclosed in double quotes that are having a comma in them. Here is the sample row

123,"ABC, DEV 23",345,534.202,NAME

I need to remove all the comma's occuring within inside the double quotes and the double quotes as well. So the above line should get parsed into as shown below

123,ABC DEV 23,345,534.202,NAME

I tried the following using sed but not giving expected results.

sed -e 's/\(".*\),\(".*\)/\1 \2/g'

Any quick tricks with sed, awk or any other unix utility please?

Answer 1

If the quotes are balanced, you will want to remove commas between every other quote, this can be expressed in awk like this:

awk -F'"' -v OFS='' '{ for (i=2; i<=NF; i+=2) gsub(",", "", $i) } 1' infile

Output:

123,ABC DEV 23,345,534.202,NAME

Explanation

The -F" instructs awk to do field-splitting on double-quote characters, this means that every other field will be the inter-quote text. The for-loop runs gsub, short for globally substitute, on every other field, replacing comma (",") with nothing (""). The 1 at the end invokes the default code-block: { print $0 }.

Answer 2

There is a good response, using sed simply one time with a loop:

echo '123,"ABC, DEV 23",345,534,"some more, comma-separated, words",202,NAME'|
  sed ':a;s/^\(\([^"]*,\?\|"[^",]*",\?\)*"[^",]*\),/\1 /;ta'
123,"ABC  DEV 23",345,534,"some more  comma-separated  words",202,NAME

Explanation:

• :a; is a label for furter branch
• s/^\(\([^"]*,\?\|"[^",]*",\?\)*"[^",]*\),/\1 / could contain 3 enclosed parts
  • first the 2nd: [^"]*,\?\|"[^",]*",\? match for a string containing no double quote, maybe followed by a coma or a string enclosed by two double quote, without coma and maybe followed by a coma.
  • than the first RE part is composed by as many repetition of previously described part 2, followed by 1 double quote and some caracteres, but no double-quote, nor comas.
  • The first RE part as to be followed by a coma.
  • Nota, the rest of the line don't need to be touched
• ta will loop to :a if previous s/ command did some change.

Once loop done, you could even add s/ */ /g:

echo '123,"ABC, DEV 23",345,534,"some more, comma-separated, words",202,NAME'|
    sed ':a;s/^\(\([^"]*,\?\|"[^",]*",\?\)*"[^",]*\),/\1 /;ta;s/  */ /g'

will suppress double spaces:

123,"ABC DEV 23",345,534,"some more comma-separated words",202,NAME

Answer 3

A general solution that can also handle several commas between balanced quotes needs a nested substitution. I implement a solution in perl, which process every line of a given input and only substitute commas in every other pair of quotes:

perl -pe 's/ "  (.+?  [^\\])  "               # find all non escaped 
                                              # quoting pairs
                                              # in a non-greedy way

           / ($ret = $1) =~ (s#,##g);         # remove all commas within quotes
             $ret                             # substitute the substitution :)
           /gex'

or in short

perl -pe 's/"(.+?[^\\])"/($ret = $1) =~ (s#,##g); $ret/ge'

You can either pipe the text you want to process to the command or specify the textfile to be processed as last command line argument.

Answer 4

I would use a language with a proper CSV parser. For example:

ruby -r csv -ne '
  CSV.parse($_) do |row|
    newrow = CSV::Row.new [], []
    row.each {|field| newrow << field.delete(",")}
    puts newrow.to_csv
  end
' < input_file

Answer 5

Your second quotes are misplaced:

sed -e 's/\(".*\),\(.*"\)/\1 \2/g'

In addition, using regular expressions tend to match the longest possible part of the text, meaning this will not work if you have more than one quoted field in the string.

A way that handles multiple quoted fields in sed

sed -e 's/\(\"[^",]\+\),\([^",]*\)/\1 \2/g' -e 's/\"//g'

This is also a way to solve this, however, with input that may contain more than one comma per quoted field the first expression in the sed would have to be repeated as many times as the maximum comma content in a single field, or until it does not change the output at all.

Running sed with the more than one expression should be more efficient than several sed processes running and a "tr" all running with open pipes.

However, this may have undesired consequences if the input is not properly formatted. i.e. nested quotes, unterminated quotes.

Using the running example:

echo '123,"ABC, DEV 23",345,534,"some more, comma-separated, words",202,NAME' \
| sed -e 's/\(\"[^",]\+\),\([^",]*\)/\1 \2/g' \
-e 's/\(\"[^",]\+\),\([^",]*\)/\1 \2/g' -e 's/\"//g'

Output:

123,ABC  DEV 23,345,534,some more  comma-separated  words,202,NAME

Answer 6

Consider csvkit:

< file csvformat -D ^ | tr -d , | tr ^ ,

Explanation

• -D ^ set the delimiter to a character not present in the file, such as carat
• tr -d , now that commas are no longer the delimiting character, delete commas
• tr ^ , convert carat back to comma

Answer 7

In perl - you can use Text::CSV to parse this, and do it trivially:

#!/usr/bin/env perl
use strict;
use warnings;

use Text::CSV; 

my $csv = Text::CSV -> new();

while ( my $row = $csv -> getline ( \*STDIN ) ) {
    #remove commas in each field in the row
    $_ =~ s/,//g for @$row;
    #print it - use print and join, rather than csv output because quotes. 
    print join ( ",", @$row ),"\n";
}

You can print with Text::CSV but it tends to preserve quotes if you do. (Although, I'd suggest - rather than stripping quotes for your output, you could just parse using Text::CSV in the first place).

Answer 8

I created a function to loop thru every character in the string.
If the character is a quotation then the check (b_in_qt) is marked true.
While b_in_qt is true, all commas are replaced with a space.
b_in_qt is set to false when the next comma is found.

FUNCTION f_replace_c (str_in  VARCHAR2) RETURN VARCHAR2 IS
str_out     varchar2(1000)  := null;
str_chr     varchar2(1)     := null;
b_in_qt     boolean         := false;

BEGIN
    FOR x IN 1..length(str_in) LOOP
      str_chr := substr(str_in,x,1);
      IF str_chr = '"' THEN
        if b_in_qt then
            b_in_qt := false;
        else
            b_in_qt := true;
        end if;
      END IF;
      IF b_in_qt THEN
        if str_chr = ',' then
            str_chr := ' ';
        end if;
      END IF;
    str_out := str_out || str_chr;
    END LOOP;
RETURN str_out;
END;

str_in := f_replace_c ("blue","cat,dog,horse","",yellow,"green")

RESULTS
  "blue","cat dog horse","",yellow,"green"

Answer 9

Using the CSV-aware utility Miller (mlr) to remove all commas from the second field of the header-less CSV data in the file called file:

$ cat file
123,"ABC, DEV 23",345,534.202,NAME

$ mlr --csv -N put '$2 = gsub($2,",","")' file
123,ABC DEV 23,345,534.202,NAME

If you want to retain the original quotes:

$ mlr --csv -N --quote-original put '$2 = gsub($2,",","")' file
123,"ABC DEV 23",345,534.202,NAME

If you have named fields (i.e. a header line), then use the name of the field instead of the 2, and drop the -N option:

mlr --csv --quote-original put '$departement = gsub($departement,",","")' file

Would you want to process all fields, then do something like

$ mlr --csv -N --quote-original put 'for (k,v in $*) { is_string(v) { $[k] = gsub(v,",","") } }' file
123,"ABC DEV 23",345,534.202,NAME

Answer 10

GoCSV makes quick and obvious work of this:

sample.csv:

Col1,Col2,Col3,Col4
01299,"ABC,DEV 23",1,0
26528,"ABC,DEV 03",0,0
38080,"DEF,STG 35",0,0
38081,"GHI,STG 19",0,0

Use its replace command to substitute all , with only in Col2:

gocsv replace -c 'Col2' -regex ',' -repl ' ' sample.csv 

yields:

Col1,Col2,Col3,Col4
01299,ABC DEV 23,1,0
26528,ABC DEV 03,0,0
38080,DEF STG 35,0,0
38081,GHI STG 19,0,0

Answer 11

Using Raku (formerly known as Perl_6)

~$ raku -pe 's:g/ \" ~ \" (<-[",]>+) ** 2..* % "," /{$0.join}/;'  file

Raku is a programming language in the Perl-family. Raku's regex notation has been significantly reworked over the approximately fifteen years of Perl6/Raku development, and many people find it easier to learn.

Above we see the familiar -pe autoprinting linewise flags, as in Perl. We also see the familiar s/// substution notation. One point of interest: substitution modifiers are denoted with a : colon and go at the head of the notation , so s:g/// stands for "substitute-global".

Within the recognition half of the s/// notation, we see two important improvements within the Raku Regex "dialect":

1. First of all, nested structures can be denoted with Raku's new ~ tilde (nested) notation, such that \" ~ \" [.+] means "one-or-more characters surrounded by " double-quotes".

2. Second of all, repeated structures can be denoted with Raku's new % modified quantifier for repeated structures. The notation [.+] ** 2..* % "," means "one-or-more characters separated by , commas with this pattern repeated ** 2..* two or more times. [If there happens to be a trailing separator (e.g. comma), use a %% instead of % in the syntax].

So, knowing Perl or PCRE syntax, at becomes much easier to read the regex notation above. To enhance this point, the syntax <-[",]> simply denotes a custom character class that does not contain either , comma or " doublequote.

Sample Input:

123,"ABC, DEV 23",345,534.202,NAME

Sample Output:

123,ABC DEV 23,345,534.202,NAME

Example Captures:

~$ raku -ne 'say $<> if m:g/ \" ~ \" (<-[",]>+)** 2..* % "," /;'  file
(｢"ABC, DEV 23"｣
 0 => ｢ABC｣
 0 => ｢ DEV 23｣)

Note: the replacement half uses {$0.join} to concatenate captured values. If you want a space inserted where the comma has been removed, simply use $0 in the replacement. Finally, for anything complex, consider using a CSV-parser like Raku's Text::CSV module. URLs below.

https://docs.raku.org/language/regexes#Tilde_for_nesting_structures
https://docs.raku.org/language/regexes#Modified_quantifier:_%,_%%
https://raku.land/github:Tux/Text::CSV
https://github.com/Tux/CSV
https://raku.org

Answer 12

Using Python

''.join([item if index % 2 == 0 else re.sub(',', '', item) for index, item in enumerate(row.split('"')) ])