how to clean a dirty csv string using php regex

provance
January 17, 2023
184 views
2 votes
3 Answers

my string may be like this:

@ *lorem.jpg,,, ip sum.jpg,dolor ..jpg,-/ ?

in fact – it is a dirty csv string – having names of jpg images

I need to remove any non-alphanum chars – from both sides of the string
then – inside the resulting string – remove the same – except commas and dots
then – remove duplicates commas and dots – if any – replace them with single ones

so the final result should be:
lorem.jpg,ipsum.jpg,dolor.jpg

I firstly tried to remove any white space – anywhere

$str = str_replace(" ", "", $str);

then I used various forms of trim functions – but it is tedious and a lot of code

the additional problem is – duplicates commas and dots may have one or more instances – for example – .. or ,,,,

is there a way to solve this using regex, pls ?

Tags: php

Answers

Can you try this :

$string = ' @ *lorem.jpg,,,,  ip sum.jpg,dolor .jpg,-/ ?';
// this will left only alphanumirics
$result = preg_replace("/[^A-Za-z0-9,.]/", '', $string);

// this will remove duplicated dot and ,
$result = preg_replace('/,+/', ',', $result);
$result = preg_replace('/.+/', '.', $result);

// this will remove ,;. and space from the end
$result = preg_replace("/[ ,;.]*$/", '', $result);

- ThomasL
- January 17, 2023 at 11:36 am
- 0 votes
0
Look at

https://www.php.net/manual/en/function.preg-replace.php

It replace anything inside a string based on pattern. s represent all space char, but care of NBSP (non breakable space, h match it )

Exemple 4
```
$str = preg_replace('/ss+/', '', $str);
```
It will be something like that
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- DiegoD
- January 17, 2023 at 11:42 am
- 0 votes
0
List of modeled steps following your words:

Step 1
- "remove any non-alphanum chars from both sides of the string"
- translated: remove trailing and tailing consecutive [^a-zA-Z0-9] characters
- regex: replace ^[^a-zA-Z0-9]*(.*?)[^a-zA-Z0-9]*$ with $1
Step 2
- "inside the resulting string – remove the same – except commas and dots"
- translated: remove any [^a-zA-Z0-9.,]
- regex: replace [^a-zA-Z0-9.,] with empty string
Step 3
- "remove duplicates commas and dots – if any – replace them with single ones"
- translated: replace consecutive [,.] as a single
  instance
- regex: replace (.{2,}) with .
- regex: replace (,{2,}) with ,
PHP Demo:

https://onlinephp.io/c/512e1
```
<?php

$subject = " @ *lorem.jpg,,, ip sum.jpg,dolor ..jpg,-/ ?";

$firstStep = preg_replace('/^[^a-zA-Z0-9]*(.*?)[^a-zA-Z0-9]*$/', '$1', $subject);
$secondStep = preg_replace('/[^a-z,A-Z0-9.,]/', '', $firstStep);
$thirdStepA = preg_replace('(.{2,})', '.', $secondStep);
$thirdStepB = preg_replace('(,{2,})', ',', $thirdStepA);

echo $thirdStepB; //lorem.jpg,ipsum.jpg,dolor.jpg
```
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