The number is converted to a string of the form "-d.ddd E+ddd" or "-d.ddd e+ddd", where each 'd' indicates a digit (0-9). ...

The number is converted to a string of the form "-d.ddd…E+ddd" or "-d.ddd…e+ddd", where each 'd' indicates a digit (0-9). The string starts with a minus sign if the number is negative. One digit always precedes the decimal point. The precision specifier indicates the desired number of digits after the decimal point.