Where both formats can present the same number of significant digits, fixed format is used.

当两种格式可以保留同样多的有效数字的时候, 优先使用固定格式.

The number of significant digits displayed in floating point numbers.

浮点类型数显示时的有效位数.

Another advantage is that you can use format specifiers other than %s, so that, for example, you can control how many significant digits the string form of a floating-point number should display.

另一个好处是你能使用不同于%s的格式化标识符，例如，以便于你能控制更多的重要的数字怎样显示浮点数字的字符串格式。