Numbers, parentheses and sed

Question

I need to clean up some text and am trying to remove numbers when they appear in parentheses. If there is more then that should remain.

Examples:

Foo 12 (bar, 13) -> Foo 12 (bar)
Foo 12 (13, bar, 14) -> Foo 12 (bar) 
Foo (14, 13) -> Foo

I thought I would start by breaking up the string and removing numbers if they appear between parentheses but it seems that I am missing something.

echo "Foo 12 (bar, 12)" | sed 's/\(.*\)\((\)\([^0-9,].*\)\([, ].*\)\([0-9].*\)\()\)/\1\2\3\6/g'

results in Foo 12 (bar,) .

I guess my approach is too atomic. What can I do?

Answer 1

If you have no problem with Perl, you could try this.

$ perl -pe 's/\s*,?\s*\b\d+\b\s*,?\s*(?=[^()]*\))//g;s/\h*\(\)$//' file
Foo 12 (bar)
Foo 12 (bar)
Foo

OR

$ perl -pe 's/(?:(?<=\()\d+,\h*|,?\h*\d+\b)(?=[^()]*\))//g;s/\h*\(\)$//' file
Foo 12 (bar)
Foo 12 (bar)
Foo

DEMO

Answer 2

Here's a general approach for problems like this, where you want to isolate a specific token and work on it, adapted for your problem:

#!/bin/sed -f

:loop                       # while the line has a matching token
/([^)]*[0-9]\+[^)])/ {      
  s//\n&\n/                 # mark it -- \n is good as a marker because it is
                            # nowhere else in the line
  h                         # hold the line!
  s/.*\n\(.*\)\n.*/\1/      # isolate the token

  s/[0-9]\+,\s*//g          # work on the token. Here this removes all numbers
  s/,\s*[0-9]\+//g          # with or without commas in front or behind
  s/\s*[0-9]\+\s*//g
  s/\s*()//                 # and also empty parens if they exist after all that.

  G                         # get the line back
                            # and replace the marked token with the result of the
                            # transformation
  s/\(.*\)\n\(.*\)\n.*\n\(.*\)/\2\1\3/

  b loop                    # then loop to get all such tokens.
}

To those who argue that this goes beyond the scope of what should reasonably be done with sed I say: True, but...well, true. But if all you see is nails, this is a way to make sed into a sledgehammer.

This can of course be written inline (although that does not help readability):

echo 'Foo 12 (bar, 12)' | sed ':loop;/([^)]*[0-9]\+[^)])/{;s//\n&\n/;h;s/.*\n\(.*\)\n.*/\1/;s/[0-9]\+,\s*//g;s/,\s*[0-9]\+//g;s/\s*[0-9]\+\s*//g;s/\s*()//;G;s/\(.*\)\n\(.*\)\n.*\n\(.*\)/\2\1\3/;b loop}'

but my advice is to put it into a file and run echo 'Foo 12 (bar, 12)' | sed -f foo.sed echo 'Foo 12 (bar, 12)' | sed -f foo.sed . Or, with the shebang like above, chmod +x foo.sed and echo 'Foo 12 (bar, 12)' | ./foo.sed echo 'Foo 12 (bar, 12)' | ./foo.sed .

I have not benchmarked this, by the way. I imagine that it is not the most efficient way to process large amounts of data.

EDIT: In response to the comments: I'm not sure what OP wants in such cases, but for the sake of completion, the basic pattern could be adapted for the other behavior like this:

#!/bin/sed -f

:loop
/(\s*[0-9]\+\s*)\|(\s*[0-9]\+\s*,[^)]*)\|([^)]*,\s*[0-9]\+\s*)\|([^)]*,\s*[0-9]\+\s*,[^)]*)/ {
  s//\n&\n/
  h
  s/.*\n\(.*\)\n.*/\1/

  s/,\s*[0-9]\+\s*,/,/g
  s/(\s*[0-9]\+\s*,\s*/(/
  s/\s*,\s*[0-9]\+\s*)/)/
  s/\s*(\s*[0-9]*\s*)//

  G
  s/\(.*\)\n\(.*\)\n.*\n\(.*\)/\2\1\3/

  b loop
}

The regex at the top looks a lot scarier now. It should help to know that it consists of the four subpatterns

(\s*[0-9]\+\s*)
(\s*[0-9]\+\s*,[^)]*)
([^)]*,\s*[0-9]\+\s*)
([^)]*,\s*[0-9]\+\s*,[^)]*)

which are or-ed together with \\| . This should cover all cases and not match things like foo12 , 12bar , and foo12bar in parentheses (unless there's a standalone number in them as well).

Answer 3

Here is an awk version:

awk -F' *\\(|\\)' '{for (i=2;i<=NF;i+=2) {n=split($i,a," *, *");f="";for (j=1;j<=n;j++) f=f (a[j]!~/[[:digit:]]/?a[j]",":""); $i=f?"("f")":"";sub(/,)/,")",$i)}}1' file
Foo 12 (bar)
Foo 12 (bar)
Foo

cat file

Foo 12 (bar, 13, more)
Foo 12 (13, bar, 14) (434, tar ,56)
Foo (14, 13)

awk -F' *\\(|\\)' '{for (i=2;i<=NF;i+=2) {n=split($i,a," *, *");f="";for (j=1;j<=n;j++) f=f (a[j]!~/[[:digit:]]/?a[j]",":""); $i=f?"("f")":"";sub(/,)/,")",$i)}}1' file
Foo 12 (bar,more)
Foo 12 (bar)  (tar)
Foo

Some more readable:

awk -F' *\\(|\\)' '
    {
    for (i=2;i<=NF;i+=2) {
        n=split($i,a," *, *")
        f=""
        for (j=1;j<=n;j++) 
            f=f (a[j]!~/[[:digit:]]/?a[j]",":"")
            $i=f?"("f")":""
            sub(/,)/,")",$i)
        }
    }
1' file

Answer 4

sed ':retry

# remove "( number )"
s/( *[0-9]* *)//

# remove first ", number" (not at first place)
s/^\(\([^(]*([^(]*)\)*[^(]*([^)]*\), *[0-9]\{1,\} *\([,)]\)/\1\3/
    t retry

# remove " number" (first place)
s/^\(\([^(]*([^(]*)\)*[^(]*(\) *[0-9]\{1,\}\(,\{0,1\}\)\()\{0,1\}\)]*/\1\4/

# case needed where only "( number)" or "()" are the result at this moment
t retry
' YourFile

• (posix version so --POSIX on GNU sed)