格式化输出

$a=get-date
$b="restart"

"On {0} ,ERP has {1}" -f $a,$b

 结果：On 2014/12/19 16:33:51 ,ERP has restart

"{0} + {1} = {2}" -f $a,$b,($a+$b)

 结果：3 + 4 = 7