> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/perl6-rosettacode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/perl6-rosettacode/programming_tasks/c/commatizing_numbers.md).

# Commatizing numbers

```perl
for ('pi=3.14159265358979323846264338327950288419716939937510582097494459231', {:6at, :5by, :ins(' ')}),
    ('The author has two Z$100000000000000 Zimbabwe notes (100 trillion).', {:ins<.>}),
    '-in Aus$+1411.8millions',
    '===US$0017440 millions=== (in 2000 dollars)',
    '123.e8000 is pretty big.',
    'The land area of the earth is  57268900(29% of the surface)  square miles.',
    'Ain\'t no numbers in this here words, nohow, no way, Jose.',
    'James was never known as  0000000007',
    'Arthur Eddington wrote: I believe there are 15747724136275002577605653961181555468044717914527116709366231425076185631031296 protons in the universe.',
    '   $-140000±100  millions.',
    '6/9/1946 was a good year for some.'
    {
        say "Before: ", .[0];
        say " After: ", .[1] ?? .[0].&commatize( |.[1] ) !! .&commatize;
    }
 
sub commatize($s, :$at = 0, :$ins = ',', :$by = 3) {
    $s.subst: :continue($at), :1st, / <[1..9]> <[0..9]>* /,
        *.flip.comb(/<{ ".**1..$by" }>/).join($ins).flip;
}
```

#### Output:

```
Before: pi=3.14159265358979323846264338327950288419716939937510582097494459231
 After: pi=3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59231
Before: The author has two Z$100000000000000 Zimbabwe notes (100 trillion).
 After: The author has two Z$100.000.000.000.000 Zimbabwe notes (100 trillion).
Before: -in Aus$+1411.8millions
 After: -in Aus$+1,411.8millions
Before: ===US$0017440 millions=== (in 2000 dollars)
 After: ===US$0017,440 millions=== (in 2000 dollars)
Before: 123.e8000 is pretty big.
 After: 123.e8000 is pretty big.
Before: The land area of the earth is  57268900(29% of the surface)  square miles.
 After: The land area of the earth is  57,268,900(29% of the surface)  square miles.
Before: Ain't no numbers in this here words, nohow, no way, Jose.
 After: Ain't no numbers in this here words, nohow, no way, Jose.
Before: James was never known as  0000000007
 After: James was never known as  0000000007
Before: Arthur Eddington wrote: I believe there are 15747724136275002577605653961181555468044717914527116709366231425076185631031296 protons in the universe.
 After: Arthur Eddington wrote: I believe there are 15,747,724,136,275,002,577,605,653,961,181,555,468,044,717,914,527,116,709,366,231,425,076,185,631,031,296 protons in the universe.
Before:    $-140000±100  millions.
 After:    $-140,000±100  millions.
Before: 6/9/1946 was a good year for some.
 After: 6/9/1946 was a good year for some.
```


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