PHP array of millions of data to eliminate data deduplication implementation Code _php tutorial

If you get a list of UID, the number is more than million lines, the format is as follows:
Copy CodeThe code is as follows:
10001000
10001001
10001002
......
10001000
......
10001111

In fact, using the characteristics of the PHP array, very good for the row weight, we first look at the definition of PHP array: The array in PHP is actually an ordered map. A map is a type that associates values to the keys. This type is optimized in many ways, so it can be used as a real array, or as a list (vector), a hash (an implementation of a mapping), a dictionary, a collection, a stack, a queue, and more possibilities. The value of an array element can also be another array. Tree structures and multidimensional arrays are also allowed.

In an array of PHP, the keys are also known as indexes, which are unique, and we can use this feature for the weight of the sample code as follows:
Copy CodeThe code is as follows:
Defines an array for storing the result after the row
$result = Array ();
Read UID list file
$fp = fopen (' test.txt ', ' R ');

while (!feof ($FP))
{
$uid = fgets ($FP);
$uid = Trim ($uid);
$uid = Trim ($uid, "\ r");
$uid = Trim ($uid, "\ n");

if ($uid = = ")
{
Continue
}
Use UID as key to see if the value exists
if (Empty ($result [$uid])
{
$result [$uid] = 1;
}
}

Fclose ($FP);

Save the results to a file
$content = ";
foreach ($result as $k = $v)
{
$content. = $k. " \ n ";
}
$fp = fopen (' Result.txt ', ' W ');
Fwrite ($fp, $content);
Fclose ($FP);
?>

More than 20 lines of code, you can be more than millions of data for the row weight, efficiency is good, very practical. Mobile phone number, email, you can also use this method for weight.

Also, this method can also be used for two files for the work of the weight, if you have two UID list file, the format and the above UID list, the sample program is as follows:
Copy CodeThe code is as follows:
Defines an array for storing the results after a row
$result = Array ();
Read the first UID list file and put $result_1
$fp = fopen (' test_1.txt ', ' R ');
while (!feof ($FP))
{
$uid = fgets ($FP);
$uid = Trim ($uid);
$uid = Trim ($uid, "\ r");
$uid = Trim ($uid, "\ n");
if ($uid = = ")
{
Continue
}
Write $result with UID key, overwrite if duplicate
$result [$uid] = 1;
}
Fclose ($FP);
Read the second UID list file and perform a sort of a load operation
$fp = fopen (' test_2.txt ', ' R ');
while (!feof ($FP))
{
$uid = fgets ($FP);
$uid = Trim ($uid);
$uid = Trim ($uid, "\ r");
$uid = Trim ($uid, "\ n");
if ($uid = = ")
{
Continue
}
Use UID as key to see if the value exists
if (Empty ($result [$uid])
{
$result [$uid] = 1;
}
}
Fclose ($FP);
$result saved in the following the result of the weight can be output to the file, code omitted
?>

When you think about it, it's easy to see that using this feature of the array can also solve more problems in our work.

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