将零填充添加到字符串

Question

如何为字符串添加“ 0”填充，以使字符串长度始终为4？

例

If input "1", 3 padding is added = 0001

If input "25", 2 padding is added = 0025

If input "301", 1 padding is added = 0301

If input "4501", 0 padding is added = 4501

Answer 1

您可以使用PadLeftvar newString = Your_String.PadLeft(4, '0');

Answer 2

myInt.ToString("D4");

Answer 3

"1".PadLeft(4, '0');