example.php

example.php

<?php
	function createStr($num = 700, $len = 6){
		if($num===0){
			return [];
		}
		$numbers = range(0, 9);
		$letters = range('a', 'z');
		$uppers = range('A', 'Z');
		$elements = array_merge($numbers, $letters, $uppers);
		$strings = [];
		for($i = 0; $i < $num; $i++){
			$str = '';
			$keys = array_rand($elements, $len);
			foreach($keys as $index){
				$str .= $elements[$index];
			}
			$strings[] = $str;
		}
		
		$strings = array_unique($strings);
		$count = count($strings);
		while($count < $num){
			$append = createStr($num - $count, $len);
			$strings = array_merge($strings, $append);
			$count = count($strings);
		}
		return $strings;
	}
	print_r(createStr(51630));