如何在php中格式化带有00前缀的数字?

I'm trying to generate invoice numbers. They should always be 4 numbers long, with leading zeros, for example :

• 1 -> 发票 0001
• 10 -> 发票 0010
• 150 -> 发票 0150

等等

推荐答案

使用str_pad().

$invID = str_pad($invID, 4, '0', STR_PAD_LEFT);