A format code can be divided into three sections that are separated by semicolons. The first part defines the format for positive values, the second part for negative values and the third part for zero. If you only specify one format code, it applies to all numbers.
格式代码由三部组合成，各部分之间用分号分隔。三个部分依次定义正数、负数和零的格式。如果仅指定一种格式代码，则所有数字都将采用这种代码。