PHP array foreach, join

1. The use of foreach
For example: $arr = array("one", "two", "three");
reset($arr);//Put the internal pointer of the array to the first element and return this The value of the element. On failure, returns FALSE.

//Array loop output 1
foreach ($arr as $value) {
echo 'Value = '.$value.'
';
}
//Array loop output 2
foreach ($ arr as $key => $value) {
echo "Key: $key; Value: $value
n";
}

Second, join Combine the array elements into a string
$in = join("', '", $arr);


3. Solutions to foreach-related exceptions
1. Problem Warning: Invalid argument supplied for foreach() in Perfect solution

Solution: Change the variables in foreach, Use is_array() to judge, or force conversion to array
For example

Php code

function getPartsNum($jsonStr){  
    $total = 0;  
    if( $jsonStr && ($jsonStr != 'NAN') && ($jsonStr != '[]') ) {  
        $detail = json_decode($jsonStr);  
        if(is_array($detail)){//或foreach ( (array)$detail as $d)  
            foreach ($detail as $d){  
                $total += $d->num;  
            }  
        }  
    }  
    return $total;  
}