How to achieve quick deduplication effect of php array elements

1. Use the array_unique method to deduplicate

To deduplicate array elements, we generally use the array_unique method. This method can deduplicate the elements in the array.

Output:

Array( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 [8] => 9)

After deduplication, the key values will be out of order. You can use array_values to reorder the key values.

2. Use array_unique method to remove duplicates for efficiency

';echo 'run time:'.(float)(($endtime-$starttime)*1000).'ms
';echo 'use memory:'.getUseMemory();/** * 获取使用内存 * @return float */function getUseMemory(){ $use_memory = round(memory_get_usage(true)/1024,2).'kb'; return $use_memory; }/** * 获取microtime * @return float */function getMicrotime(){ list($usec, $sec) = explode(' ', microtime()); return (float)$usec + (float)$sec; }?>

unique count:99
run time:653.39303016663ms
use memory:5120kb

Use thearray_uniquemethod to remove duplicates. The running time takes about650msand the memory usage is about5m

3. Faster Array deduplication method

php has a key-value exchange method array_flip. We can use this method to deduplicate. Because of key-value exchange, the original duplicate values will become the same key.
Then perform a key-value exchange and exchange the keys and values back to complete deduplication.

';echo 'run time:'.(float)(($endtime-$starttime)*1000).'ms
';echo 'use memory:'.getUseMemory();/** * 获取使用内存 * @return float */function getUseMemory(){ $use_memory = round(memory_get_usage(true)/1024,2).'kb'; return $use_memory; }/** * 获取microtime * @return float */function getMicrotime(){ list($usec, $sec) = explode(' ', microtime()); return (float)$usec + (float)$sec; }?>

unique count:99
run time:12.840032577515ms
use memory:768kb

Usearray_flipmethod to remove duplicates, the running time takes about18ms, the memory usage is about2m

. Therefore, using thearray_flipmethod to remove duplicates takes longer than using thearray_uniquemethod. The running time is98%, memory usage reduced4/5;

This article explains how to achieve the rapid deduplication effect of PHP array elements. For more related content, please pay attention to the PHP Chinese website.

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