Built-in function in Python Script



Python has a few other built-in functions for working with numeric types they are listed below.

  • Absolute value—abs
  • Convert two numbers to a common type—coerce(x, y)
  • Quotient and remainder—divmod(a, b)
  • Power—pow(x, y [, z])
  • Round—round(x [, n])



Absolute value—abs

The abs(x) function takes the absolute value of any integer, long integer, or floating
point number:
>>> abs(-5.0)
5.0
>>> abs(-20L)
20L
When applied to a complex number, this function returns the magnitude of the number, which is the distance from that point to the origin in the complex plane. Python calculates the magnitude just like the length of a line in two dimensions: for a complex number (a + bj), the magnitude is the square root of a squared plus b squared:
>>> abs(5 - 2j)
5.3851648071345037


Convert two numbers to a common type—coerce(x, y)

The coerce function applies the previously explained numeric conversion rules to two numbers and returns them to you as a tuple 
>>> coerce(5,2L)
(5L, 2L)
>>> coerce(5.5,2L)
(5.5, 2.0)
>>> coerce(5.5,5 + 2j)
((5.5+0j), (5+2j))

Quotient and remainder—divmod(a, b)

This function performs long division on two numbers and returns the quotient and the remainder:
>>> divmod(5,2)
(2, 1)
>>> divmod(5.5,2)
(2.0, 1.5)

Power—pow(x, y [, z])

The pow function is similar to the power (**) operator
>>> pow(5,2)
25
>>> pow(1.2,2.1)
1.4664951016517147
As usual, Python coerces the two numbers to a common type if needed. If the resulting type can’t express the correct result

>>> pow(2.0,-1) # The coerced type is a floating point.
0.5
>>> pow(2,-1) # The coerced type is an integer.
Traceback (innermost last):
File “<interactive input>”, line 1, in ?
ValueError: integer to the negative power
An optional third argument to pow specifies the modulo operation to perform on
the result:
>>> pow(2,5)
32
>>> pow(2,5,10)
2
>>> (2 **5) % 10
2

The result is the same as using the power and modulo operators, but Python arrives at the result more efficiently. (Speedy power-and-modulo is useful in some types of cryptography.)

Round—round(x [, n])

This function rounds a floating point number x to the nearest whole number. Optionally, you can tell it to round to n digits after the decimal point:
>>> round(5.567)
6.0
>>> round(5.567,2)
5.57

No comments:

Post a Comment