How do I replace any number of character occurences with one occurrence?

[OM2]

How do I replace any number of character occurences with one occurrence?

 

Let's say I have:

 

aaa

aaaaaa

aaaaa

aaaaaaaa

 

All of the above should be replaces with a single 'z' character say for example

 

I can do exact matches, say for 'aaaaaa' - but am unsure how I can do for any number

 

I'm sure it should be possible to do using one line of code - but I'm just not sure where to start!

 

Thanks

 

 

OM

[ialsoagree]

You might want to have a look at str_replace:

http://www.php.net/manual/en/function.str-replace.php

 

If you check out the optional $count variable you should be able to figure out a way of creating a loop to do this for you.

[MatthewJ]

Or use preg_replace

[OM2]

oh

i thought there would be a more elegant regular expression solution 

 

i can easily write a function that does unlimited number of loops where one character at a time is removed until we get left with a single character

 

but it would have thought this would be highly inefficient way and was (blindly) sure that there would be a better way!

 

hmmm 

[OM2]

Or use preg_replace

aaah... thats more like it

the problem is that i'm unsure about the weird regular expressions!

 

i read the function up and i think there's something that does what i need:

 

<?php

$str = 'foo  o';

$str = preg_replace('/\s\s+/', ' ', $str);

// This will be 'foo o' now

echo $str;

?>

 

now... i'm not sure how the regular expression works!

how do u make sure that u r just left with one single space?

how does it only search for 2 or more spaces - but ignores single spaces?

 

what i actually want to do is replace all space characters with a '-' character

if there is a single space, then this gets replaced with a single '-'

if there is 2 or more spaces, then these also get replaced by a single '-' character

 

not sure where to start!

[JAY6390]

$str = preg_replace('%\s+%','-', $str);

[OM2]

thank u!

trying out now

[cags]

The \s will match any whitespace character is that the intention or do you just with to replace the space character? If the latter then you can use this regex pattern.

 

~[ ]+~

 

Just incase somebody decides to point it out, this will work just as well...

 

~ +~

 

... it's up to you as to which you find easier to read. Personally I find the first easier at a glance.

[OM2]

thank u - that helps a lot

it's probably just space character that i want to catch - but i think i'd go for whitespace - just incase

 

what i've got is a system where users can duplicate directories

i want the user to be only allowed to enter characters and numbers when choosing a new name for the duplicated directory

ALL other characters should be left out AND white space characters need to be replaced with a single '-' (no matter how many of them)

 

hmmm... the more i think of it... i think what i want could be done in a regular expression?

not sure + i'm a little confused when it comes to reading or writing them   

[cags]

You could have probably used something like...

 

preg_match("~^[a-z_-]{3,8}$~i", $input);

 

... to validate the string. That will check that $input is a string that is between 3 and 8 characters long, contains only the values a trough z underscore and dash (or whatever you wish to call it). The i at the end makes it case insensitive so you can use upper or lower case.

[JAY6390]

if you want to do that it's pretty easy

$input = 'random            string for 4352345 your DiReCtOrY';
$input = preg_replace('/[^\w\s]+/i','', trim($input));
$input = preg_replace('/\s+/','-', trim($input));

 

[OM2]

awesome: thank u for all the replies!

[JAY6390]

Just realised I copied and pasted the trim for the second preg_replace. That shouldn't be there

[OM2]

i noticed before as well

thanks