Section 5.8. Related Modules

5.8. Related Modules

There are a number of modules in the Python standard library that add on to the functionality of the operators and built-in functions for numeric types. Table 5.8 lists the key modules for use with numeric types. Refer to the literature or online documentation for more information on these modules.

Table 5.8. Numeric Type Related Modules

Module	Contents
decimal	Decimal floating point class Decimal
array	Efficient arrays of numeric values (characters, ints, floats, etc.)
math/cmath	Standard C library mathematical functions; most functions available in math are implemented for complex numbers in the cmath module
operator	Numeric operators available as function calls, i.e., operator.sub(m, n) is equivalent to the difference (m - n) for numbers m and n
random	Various pseudo-random number generators (obsoletes rand and wHRandom)

For advanced numerical and scientific mathematics applications, there are well-known third-party packages Numeric (NumPy) and SciPy, which may be of interest to you. More information on those two packages can be found at:

http://numeric.scipy.org/

http://scipy.org/

Core Module: random

The random module is the general-purpose place to go if you are looking for random numbers. This module comes with various pseudo-random number generators and comes seeded with the current timestamp so it is ready to go as soon as it has loaded. Here are some of the most commonly used functions in the random module:

randint()	Takes two integer values and returns a random integer between those values inclusive
randrange()	Takes the same input as range() and returns a random integer that falls within that range
uniform()	Does almost the same thing as randint(), but returns a float and is inclusive only of the smaller number (exclusive of the larger number)
random()	Works just like uniform() except that the smaller number is fixed at 0.0, and the larger number is fixed at 1.0
choice()	Given a sequence (see Chapter 6), randomly selects and returns a sequence item

We have now come to the conclusion of our tour of all of Python's numeric types. A summary of operators and built-in functions for numeric types is given in Table 5.9.

Table 5.9. Operators and Built-in Functions for All Numeric Types

Operator/Built-in	Description	Int	Long	Float	Complex	Result[a]
abs()	Absolute value	•	•	•	•	number[a]
chr()	Character	•	•			str
coerce()	Numeric coercion	•	•	•	•	tuple
complex()	Complex factory function	•	•	•	•	complex
divmod()	Division/modulo	•	•	•	•	tuple
float()	Float factory function	•	•	•	•	float
hex()	Hexadecimal string	•	•			str
int()	Int factory function	•	•	•	•	int
long()	Long factory function	•	•	•	•	long
oct()	Octal string	•	•			str
ord()	Ordinal			(str)		int
pow()	Exponentiation	•	•	•	•	number
round()	Float rounding			•		float
**[b]	Exponentiation	•	•	•	•	number
+[c]	No change	•	•	•	•	number
-[c]	Negation	•	•	•	•	number
~[c]	Bit inversion	•	•			int/long
**[b]	Exponentiation	•	•	•	•	number
*	Multiplication	•	•	•	•	number
/	Classic or true division	•	•	•	•	number
//	Floor division	•	•	•	•	number
%	Modulo/remainder	•	•	•	•	number
+	Addition	•	•	•	•	number
-	Subtraction	•	•	•	•	number
<<	Bit left shift	•	•			int/long
>>	Bit right shift	•	•			int/long
&	Bitwise AND	•	•			int/long
^	Bitwise XOR	•	•			int/long
|	Bitwise OR	•	•			int/long

^[a] A result of "number" indicates any of the four numeric types, perhaps the same as the operands.

^[b] ** has a unique relationship with unary operators; see Section 5.5.3 and Table 5.2.

^[c] Unary operator.