可以使用正则表达式匹配来测试:

You can use a regular expression match to test it:

if($substring -match "^\d+$")
{
   # Do something
}

这应该适用于任何只包含数字的字符串(即正整数).如果要包含负整数，请将模式更改为 ^-?\d+$.

This should work for any string which contains only digits (i.e. is a positive integer). Change the pattern to ^-?\d+$ if you want to include negative integers.