PHP determines that an array is a subset of another array _php tutorial

Objective
Today, the process of completing an algorithm, there are several requirements module, which has to determine whether a $ A array is a subset of $b array, perhaps recently I write C more, directly with the For loop implementation, but feel the code is larger, not elegant! In the QQ group brainstorming a bit, found that many of the system functions provided by PHP can be called, here to record

Demand
Minimum time complexity to determine if a $ A array is a subset of the $b array
[PHP]
Quickly determine if a $ A array is a subset of the $b array
$a = array (135,138);
$b = Array (135,138,137);

Quickly determine if a $ A array is a subset of the $b array
$a = array (135,138);
$b = Array (135,138,137);

Implementation method
Here are three ways to approach, the idea is actually the same, the difference lies in the implementation of the Code

For loop traversal
[PHP]
$flag = 1;
foreach ($a as $va) {
if (In_array ($va, $b)) {
Continue
}else {
$flag = 0;
Break
}
}

if ($flag) {
echo "Yes";
}else {
echo "No";
}

$flag = 1;
foreach ($a as $va) {
if (In_array ($va, $b)) {
Continue
}else {
$flag = 0;
Break
}
}

if ($flag) {
echo "Yes";
}else {
echo "No";
}

Use of Array_diff

Code
[PHP]
$c = Array_diff ($a, $b);
Print_r ($c);
$flag = Empty ($c)? 1:0;

if ($flag) {
echo "Yes";
}else {
echo "No";
}

$c = Array_diff ($a, $b);
Print_r ($c);
$flag = Empty ($c)? 1:0;

if ($flag) {
echo "Yes";
}else {
echo "No";
}

Use of Array_intersect

Code
[PHP]
if ($a = = Array_intersect ($a, $b)) {
$flag = 1;
}else {
$flag = 0;
}

if ($flag) {
echo "Yes";
}else {
echo "No";
}

if ($a = = Array_intersect ($a, $b)) {
$flag = 1;
}else {
$flag = 0;
}

if ($flag) {
echo "Yes";
}else {
echo "No";
}

Postscript
A good mentor can not only teach me how to learn, but also teach me how to do things, be grateful, have the responsibility

http://www.bkjia.com/PHPjc/477471.html www.bkjia.com true http://www.bkjia.com/PHPjc/477471.html techarticle Preface the process of completing an algorithm today, there are several requirements module, in which there is a judge of a $ A array is a subset of $b array, perhaps recently I write C more, directly with the For loop implementation ...

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