Pyhton Chapter#6: Numbers

Ankur Kulhari

In python numeric data types store numeric values. Number objects are created when a value is assigned to them.

num1 = 5
num2 = 10

Four different numerical types are supported in python:

  1. int (signed integers)
  2. long (long integers, they can also be represented in octal and hexadecimal)
  3. float (decimal/real values)
  4. complex (complex numbers)
Mathematical Functions

Python includes following functions for numbers:

Function Description
abs(x) It returns the absolute value of x
math.ceil(x) It returns the ceiling of x: nearest larger integer. Ex: math.ceil(3.1) = 4
cmp(x, y) It returns 1 if x > y, 0 if x == y, or -1 if x < y
exp(x) It returns ex. In python 3 you have to use math.exp(1)
fabs(x) It returns the absolute value of x in float
math.floor(x) The floor of x: nearest smaller integer. Ex: math.floor(x)
math.log(x) It returns the natural logarithm of x, where x> 0. You can define the base as math.log(x,base)
math.log10(x) It returns the logarithm base-10 of x, where x> 0
max(x1, x2,…) It returns the largest among passed arguments
min(x1, x2,…) It returns the smallest of among passed arguments
math.modf(x) It returns two tuple value consisting of (fractional, integer parts of x) and both parts have the same sign as x. The integer part is returned as a float.
pow(x, y) It returns x**y.
round(x, n) It returns rounded value of x, to n digits from the decimal point. Python rounds to greater integer for a tie-breaker: round(0.5) is 1.0 and round(-0.5) is -1.0.
math.sqrt(x) It returns the square root of x, where x > 0

Random Number Functions

Python includes following functions that are widely used. You have to import random library to use these functions.

Function Description
choice(seq) It returns a randomly selected item from the passed argument, that could be:sequence, tuple, or string,
random.randrange (start, last, step) It returns a randomly selected value between start and stop, with step value as step. Ex: random.randrange(2,10,1), returns a random value from 2, 3, 4, 5, 6, 7, 8, 9, 10
random.random() It returns a random float vaule x, such that 0 ≤ x < 1
random.seed(x) In python random numbers are generated by performing some operation on a number and usually this number is a previously generated random number. So for the 1st time x is used to generate the random number. If you provide the same value of x, the same random numbers will be generated. Best is to use current time as x in seed.
random.shuffle(list) It randomizes the items of a list in place. Returns None. Ex:x=[1,2,3,4],random.shuffle(x),x= [2, 1, 3, 4]
uniform(x, y) It returns a random float value f, such that x ≤ f &t; y

Trigonometric Functions

In python trigonometric functions are avaiabe in math ibrary.
math.acos(x), math.asin(x), math.atan(x), math.atan2(y, x), math.cos(x), math.hypot(x, y), math.sin(x), math.tan(x), math.degrees(x), math.radians(x).

Mathematical Constants

In python pi and e are the two mathematical constants. They can be used as math.pi and math.e.

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