To determine odd or even it's faster and more efficient to use the bitwise & operator:
$a = 3;
if ($a & 1) {
    echo 'odd';
} else { 
    echo 'even';
}
// returns 'odd'
PHP - Manual: MOD
2025-11-04
<?php
/*
 * Makes the value of "result" congruent to "value1" modulo "value2".
 * opcode number: 5
 */
echo 6 % 3;
?>
Function name: (null)
Compiled variables: none
| line | # | op | fetch | ext | return | operands | 
|---|---|---|---|---|---|---|
| 6 | 0 | MOD | ~0 | 6,3 | ||
| 1 | ECHO | ~0 | ||||
| 7 | 2 | RETURN | 1 | 
To determine odd or even it's faster and more efficient to use the bitwise & operator:
$a = 3;
if ($a & 1) {
    echo 'odd';
} else { 
    echo 'even';
}
// returns 'odd'
A function to handle integers of any length, including negatives. Returns remainder but also calculates division in the process (could be useful in some cases).
<?php
function remainder($dividend, $divisor) {
    if ($dividend == 0 || $divisor == 0) return 0;
    $dividend .= '';
    $remainder = 0;
    $division = '';
    
    // negative case
    while ($dividend < 0) {
        $dividend += $divisor;
        if ($dividend >= 0) return $dividend;
    }
    
    // positive case
    while (($remainder.$dividend)*1 > $divisor) {
        // get remainder big enough to divide
        while ($remainder*1 < $divisor) {
            $remainder .= $dividend[0];
            $remainder *= 1;
            $dividend = substr($dividend, 1);
        }
        
        // get highest multiplicator for remainder
        $mult = floor($remainder / $divisor);
        // add multiplicator to division
        $division .= $mult.'';
        // subtract from remainder
        $remainder -= $mult*$divisor;
    }
    
    // add remaining zeros if any, to division
    if (strlen($dividend) > 0 && $dividend*1 == 0) {
        $division .= $dividend;
    }
    
    return $remainder;
}
Might be helpful:
I had to create and "INSERT INTO" on every 50th row:
<?php
$lineBreak = 50;
$tableName = 'user';
$tableFields = 'id, name, password';
?>
in the loop:
<?php
if ($counter === 0 || $counter % $lineBreak === 0) {
    echo "INSERT INTO $tableName ($tableFields) VALUES (";
} else {
    echo ' (';
}
// add values comma-delimited
if ($counter === 0 || $counter % $lineBreak === 0) {
    $insertStmt .= ');';
} else {
    $insertStmt .= '),';
}
?>
(in my case I had to check if $no % $o === 0)
官方地址:https://www.php.net/manual/en/internals2.opcodes.mod.php