GNU Info

(python2.1-ref.info)Floating point literals

---

Next: Imaginary literals Prev: Integer and long integer literals Up: Literals

---

Enter node , (file) or (file)node

Floating point literals
-----------------------

Floating point literals are described by the following lexical
definitions:

     floatnumber:    pointfloat | exponentfloat
     pointfloat:     [intpart] fraction | intpart "."
     exponentfloat:  (nonzerodigit digit* | pointfloat) exponent
     intpart:        nonzerodigit digit* | "0"
     fraction:       "." digit+
     exponent:       ("e"|"E") ["+"|"-"] digit+

Note that the integer part of a floating point number cannot look like
an octal integer, though the exponent may look like an octal literal
but will always be interpreted using radix 10.  For example, `1e010' is
legal, while `07.1' is a syntax error.  The allowed range of floating
point literals is implementation-dependent.  Some examples of floating
point literals:

     3.14    10.    .001    1e100    3.14e-10

Note that numeric literals do not include a sign; a phrase like `-1' is
actually an expression composed of the operator `-' and the literal `1'.