Splitting text

Question

I want to know is there any way to split text like this:

123456789 into 123-456-789

as to add "-" after every 3 characters?

Just wanted to know, as I know the reverse, but how to do this is over my head. ;)

and also if the text is

ABCDEFGHI OR A1B2C3D4E or any other format 
without any space between the characters !

languge : PHP only

Answer 1

In Perl:

#!/usr/bin/perl

use strict;
use warnings;

my $string = "123456789";
$string =~ /(\d{3})(\d{3})(\d+)/;

print "$1-$2-$3"

Answer 2

You can do it with (among other means) a regular expression match and replace. The exact syntax depends on the tool or programming language you are using. For instance, one way to do it in Perl would be

$a = "123456789";
$a =~ s/(\d{3})/$1-/g;
chop($a);
print $a;

Line 2 replaces every 3 digits for the same 3 digits and a dash. With chop() we delete the trailing dash.

There is another question here. What to do when the string doesn't contain a multiple by 3 amount of digits? If such strings were allowed, then the above snippet would need modification.

Also, depending on the specifics of the case, you might get away with simple substring replacement, or string slicing.

Answer 3

In the interest of completeness, here is a Python solution:

>>> a = "123456789"
>>> a[0:3] + "-" + a[3:6] + "-" + a[6:9]
'123-456-789'

Since you updated your question to specify a PHP solution, this should work:

substr($a, 0, 3) . "-" . substr($a, 3, 3) . "-" . substr($a, 6, 3)

See substr for more information on this function. This will work not only for digits, but for alphabetic characters too.

Answer 4

I'm not a big fan of regexes for simple string extraction (especially fixed length extractions), preferring them for slightly more complex stuff. Almost every language has a substring function so, presuming your input has already been validated, a simple (pseudo-code since you haven't specified a language):

s = substring (s,0,3) + "-" + substring (s,3,3) + "-" + substring (s,6,3)

If you want it every three characters for a variable length string (with odd size at the end):

t = ""
sep = ""
while s != "":
    if s.len <= 3:
        t = t + sep + s
        s = ""
    else:
        t = t + sep + substring (s,0,3)
        s = substring (s,3)
    sep = "-"
s = t

Answer 5

I think that this can be sanely done in a regex with lookahead:

s/(.{3})(?=.)/$1-/g

Since you mentioned PHP in a comment:

preg_replace ("/(.{3})(?=.)/", "$1-", $string);

edit: After VolkerK showed wordwrap, I found chunk-split in the documentation:

$new_string = chunk_split ($string, 3, '-');

This has the advantage that it also works when there are spaces in the string (wordwrap would prefer to break at the spaces).

Answer 6

One more Perl example. This doesn't remove final groups smaller than three, and it leaves initial groups of less than three digits alone. It's based (pretty shamelessly) on the "money numbers" example in Learning Perl (page 212 of the 5th ed):

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

print "Gimme' a number: ";
chomp(my $number = <STDIN>);

1 while ($number =~ s/([0-9]{3})([0-9]+)/$1-$2/);

print "Now it's $number\n";

Answer 7

Yet another Python version:

>>> x="123456789"
>>> out=[x[i:i+3] for i in xrange(0, len(x), 3)]
>>> print "-".join(out)
123-456-789

Answer 8

For any language:

• Create an empty string variable called "result"
• Create an integer counter variable, "i", which increments until the length of the original string (the one with the number)
• Append each character from the original string to "result"
• If i modulo 3 (usually % or mod) is zero, append a dash to "result"

Answer 9

<?php
$i = '123456789';
echo 'result: ', wordwrap($i, 3, '-', true);

prints

result: 123-456-789

see http://php.net/wordwrap