Be sure to have unique array entry - php

Question

I have a file which contains something like :
toto;145
titi;7
tata;28
I explode this file to have an array.
I am able to display the data with that code :
foreach ($lines as $line_num => $line) {
$tab = explode(";",$line);
//erase return line
$tab[1]=preg_replace('/[\r\n]+/', "", $tab[1]);
echo $tab[0]; //toto //titi //tata
echo $tab[1]; //145 //7 //28
}
I want to be sure that data contained in each $tab[0] and $tab[1] is unique.
For example, I want a "throw new Exception" if file is like :
toto;145
titi;7
tutu;7
tata;28
or like :
toto;145
tata;7
tata;28
How can I do that ?

Answer 1

Convert your file to array with file(), and convert to associative array with additional duplication checking.
$lines = file('file.txt', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
$tab = array();
foreach ($lines as $line) {
list($key, $val) = explode(';', $line);
if (array_key_exists($key, $tab) || in_array($val, $tab)) {
// throw exception
} else {
$tab[$key] = $val;
}
}

Answer 2

Store them as key => value pairs in an array, and check whether each key or value already exists in your array as you are looping through the file. You can check for an existing key with array_key_exists and an existing value with in_array.

Answer 3

One simple is using array_unique, save the parts (tab[0] and tab[1]) into two separate arrays after you explode, name them for example $col1 and $col2 and then, you could do this simple test:
<?php
if (count(array_unique($col1)) != count($col1))
echo "arrays are different; not unique";
?>
PHP will turn your array parts into unique, if duplicated entrys exist, so if the size of the new array differs from the original, it means that it was not unique.

Answer 4

//contrived file contents
$file_contents = "
toto;145
titi;7
tutu;7
tata;28";
//split into lines and set up some left/right value trackers
$lines = preg_split('/\n/', trim($file_contents));
$left = $right = array();
//split each line into two parts and log left and right part
foreach($lines as $line) {
$splitter = explode(';', preg_replace('/\r\n/', '', $line));
array_push($left, $splitter[0]);
array_push($right, $splitter[1]);
}
//sanitise left and right parts into just unique entries
$left = array_unique($left);
$right = array_unique($right);
//if we end up with fewer left or right entries than the number of lines, error...
if (count($left) < count($lines) || count($right) < count($lines))
die('error');

Answer 5

Use associative arrays with keys "toto", "tata" etc.
To check whether a key exists you can use array_key_exists or isset.
BTW. Instead of preg_replace('/[\r\n]+/', "", $tab[1]), try trim (or even rtrim).

Answer 6

While you're traversing the array add the values to an existing array, i.e. placeholder, which will be used to check if the value exists or not via in_array().
<?php
$lines = 'toto;145 titi;7 tutu;7 tata;28';
$results = array();
foreach ($lines as $line_num => $line) {
$tab = explode(";",$line);
//erase return line
$tab[1]=preg_replace('/[\r\n]+/', "", $tab[1]);
if(!in_array($tab[0]) && !in_array($tab[1])){
array_push($results, $tab[0], $tab[1]);
}else{
echo "value exists!";
die(); // Remove/modify for different exception handling
}
}
?>