array-key-exists | 易学教程

array_key_exists($key, $array) vs !empty($array[$key])

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问题 I've seen a lot of people do the former, is there any performance benefit doing one vs the other? Or is it just an eye candy? I personally use the latter every time as it is shorter and personally more readable to me. 回答1: The other responses focus on the differences between the two functions. This is true, but if the source array does not contain null or 0 or "" , ... (empty values) values you can benchmark the speed of the two functions: <?php function makeRandomArray( $length ) { $array =

Find a key exists in the sub keys of an array?

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问题 How can I check if a key exists in the sub keys of an array? And if that key of the item is found then return that item? For instance, I have this array, Array ( [0] => Array ( [a] => Array ( [quantity_request] => 1 [time_created] => 1339688613 [variant] => Array ( ) ) ) [1] => Array ( [b] => Array ( [quantity_request] => 1 [time_created] => 1339688631 [variant] => Array ( ) ) ) [2] => Array ( [c] => Array ( [quantity_request] => 1 [time_created] => 1339688959 [variant] => Array ( ) ) ) ) I

Find a key exists in the sub keys of an array?

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Why is array_key_exists 1000x slower than isset on referenced arrays?

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问题 I have found that array_key_exists is over 1000x slower than isset at check if a key is set in an array reference. Does anyone that has an understanding of how PHP is implemented explain why this is true? EDIT: I've added another case that seems to point to it being overhead required in calling functions with a reference. Benchmark Example function isset_( $key, array $array ) { return isset( $array[$key] ); } $my_array = array(); $start = microtime( TRUE ); for( $i = 1; $i < 10000; $i++ ) {

Pattern Output, stuck

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问题 Pretty new to all this, but here i go... I need to make 2 patterns using a table (without borders) and for-loops: 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 1 2 3 4 5 6 I did work this one out with (probably not the easiest way tho, but it works): <table> <b>Patroon I</b> <?php $pattern = array(); for($pyramid = 1; $pyramid <=6; $pyramid++){ $pattern[$pyramid] = $pyramid; echo "<tr> <td class='td1'>" . $pattern[1] . "</td>"; if(array_key_exists(2, $pattern)){ echo "<td class='td1'>" . $pattern[2] . "</td>

Why is array_key_exists 1000x slower than isset on referenced arrays?

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I have found that array_key_exists is over 1000x slower than isset at check if a key is set in an array reference. Does anyone that has an understanding of how PHP is implemented explain why this is true? EDIT: I've added another case that seems to point to it being overhead required in calling functions with a reference. Benchmark Example function isset_( $key, array $array ) { return isset( $array[$key] ); } $my_array = array(); $start = microtime( TRUE ); for( $i = 1; $i < 10000; $i++ ) { array_key_exists( $i, $my_array ); $my_array[$i] = 0; } $stop = microtime( TRUE ); print "array_key