Split file up based on delimiters in php - which is the best to use?

Question

I am trying to parse a file using php but I am not sure of the best way to do it. The file consists of stuff like:

saturn+5 57 space+shuttle 34 gemini 12 mercury 2 soyuz+tm 1

What I'm trying to do is split it up and populate a hash map, so..

$inventory["saturn+5"] = "57";
$inventory["space+shuttle"] = "34";
and so on.

I don't know how to tackle this.

I am trying to write a bit of regex to process the file to separate out the fields but I'm not having much luck and was wondering if I should try using a different approach using split() or explode().

Well, `explode` would be quite a cumbersome approach. What are you regex attempts? — mario, Jun 06 '14 at 01:50
My first attempt was something like '/([.*]\s[0-9]*)/' but I don't think this would give me what I wanted. It would give me something like $splitstring[0]="saturn+5"; $splitstring[1]="57";$splitstring[2]="space+shuttle"; etc. So I'd have to loop through the array, so the odd numbered indices would be the key and the even indices the value, but this struck me as cumbersome. I thought there was a one-step approach that would do the odd/even index assignation immediately. — user3713442, Jun 06 '14 at 01:57

score 2 · Answer 1 · answered Jun 06 '14 at 01:55

2

my crude approach:

<?php
echo '<pre>';
$str="saturn+5 57 space+shuttle 34 gemini 12 mercury 2 soyuz+tm 1";

//break it on space
$e=explode(' ',$str);

//reindex array to start from 1
array_unshift($e, "phoney");
unset($e[0]);

print_r($e);
$inventory=array();
foreach ($e as $k=>$v){

//detects odd key   
if(($k+2)%2==1) {

$inventory[$v]= $e[$k+1];

    }

}

print_r($inventory);

demo: http://codepad.viper-7.com/PN6K8m

output:

Array
(
    [saturn+5] => 57
    [space+shuttle] => 34
    [gemini] => 12
    [mercury] => 2
    [soyuz+tm] => 1
)

answered Jun 06 '14 at 01:55

Why do you need to reindex the array? – Casimir et Hippolyte Jun 06 '14 at 02:20
You can use a negation to avoid this step: `foreach ($e as $k => $v) { if (!($k%2)) $inventory[$v] = $e[$k+1]; }` – Casimir et Hippolyte Jun 06 '14 at 02:25
i come from the "get it done" school of programming, im not paid to think – Jun 06 '14 at 02:27

fin · Answer 2 · 2014-06-06T02:16:39.217

2

If it's always in that order, this will work:

<?

$foo = 'saturn+5 57 space+shuttle 34 gemini 12 mercury 2 soyuz+tm 1';
$foo_array = preg_split('/\s+/', $foo);

$hash = array();
for ($i = 0; $i < count($foo_array); $i++){
    $i % 2 ? null : $hash[$foo_array[$i]] = $foo_array[++$i];
}

print_r($hash);
?>

Output:

php foo.php
Array
(
    [saturn+5] => 57
    [space+shuttle] => 34
    [gemini] => 12
    [mercury] => 2
    [soyuz+tm] => 1
)

edited Jun 06 '14 at 02:16

answered Jun 06 '14 at 01:56

fin

333
1
4

Thanks, this almost works; it seems that there are newline characters in the file, or something odd I hadn't accounted for. I get this: Array ( [ saturn+5] => 57 space_shuttle [34 gemini] => 12 mercury [2 soyuz+tm] – user3713442 Jun 06 '14 at 02:05
@user3713442: you can use `trim` before. – Casimir et Hippolyte Jun 06 '14 at 02:10
`$foo_array = preg_split('/\s+/', $foo);` – Jun 06 '14 at 02:12
you can improve the loop with:`$length=count($foo_array);for ($i = 0; $i < $length ;$i++){ $hash[$foo_array[$i]] = $foo_array[++$i]; }` – Casimir et Hippolyte Jun 06 '14 at 02:14

hwnd · Accepted Answer · 2014-06-06T02:13:40.473

2

Here's my approach using regular expression.

$data = 'saturn+5 57 space+shuttle 34 gemini 12 mercury 2 soyuz+tm 1';

$inventory = array();

preg_match_all('/(\S+) (\S+)/', $data, $matches);
foreach ($matches[1] as $index => $match) {
   $inventory[$match] = $matches[2][$index];
}
print_r($inventory);

Output

Array
(
    [saturn+5] => 57
    [space+shuttle] => 34
    [gemini] => 12
    [mercury] => 2
    [soyuz+tm] => 1
)

edited Jun 06 '14 at 02:13

answered Jun 06 '14 at 01:58

hwnd

69,796
4
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There are some great solutions on this page, many thanks. I went for the option above as it was the first one I tried and it worked. – user3713442 Jun 06 '14 at 02:17

score 2 · Answer 4 · answered Jun 06 '14 at 02:01

2

It's actually quite trivial with a regex:

preg_match_all("/  ([\w+]+)  \s  (\d+)  /x", $string, $m);
$assoc = array_combine($m[1], $m[2]);

You're just looking for a combination of alphanumeric characters \w and optional + signs, then a space, then a \d decimal.

array_combine will give you the associative array.

answered Jun 06 '14 at 02:01

mario

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+1 for some really elegant regex! But it should work fine like this `/([\w+]+)\s(\d+)/x`, correct? – Giacomo1968 Jun 06 '14 at 02:07
1

@JakeGould yes, the `x` modifier is for readability with the regex really. – hwnd Jun 06 '14 at 02:09
@hwnd Ahhhh! Now I know what the `x` modifier is for! Starring this question. Awesome stuff. – Giacomo1968 Jun 06 '14 at 02:10

Split file up based on delimiters in php - which is the best to use?

4 Answers4