CODEWITHSUNDEEP
phpregexdelimiter
james
james

Reputation:

Inject a delimiter between sets of N characters in a string

I want to know is there any way to add mid-string delimiters in text like this:

123456789 into 123-456-789

Basically, add "-" between every 3 characters?

Also if the text is

Upvotes: 6

Views: 429

Answers (7)

Svante
Svante

Reputation: 51561

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).

Upvotes: 2

VolkerK
VolkerK

Reputation: 96199

<?php
$i = '123456789';
echo 'result: ', wordwrap($i, 3, '-', true);
prints
result: 123-456-789

see http://php.net/wordwrap

Upvotes: 5

Greg Hewgill
Greg Hewgill

Reputation: 994897

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.

Upvotes: 2

Chris S
Chris S

Reputation: 65476

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"

Upvotes: 1

paxdiablo
paxdiablo

Reputation: 882776

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

Upvotes: 3

Vinko Vrsalovic
Vinko Vrsalovic

Reputation: 340496

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.

Upvotes: 0

Alan Haggai Alavi
Alan Haggai Alavi

Reputation: 74292

In Perl:

#!/usr/bin/perl

use strict;
use warnings;

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

print "$1-$2-$3"

Upvotes: 0

Related Questions