7.9 Universal Functions

  • Standalone universal functions (ufuncs) perform element-wise operations using one or two array or array-like arguments (like lists)
  • Each returns a new array containing the results
  • Some ufuncs are called when you use array operators like + and *
  • Create an array and calculate the square root of its values, using the sqrt universal function
In [1]:
import numpy as np
In [2]:
numbers = np.array([1, 4, 9, 16, 25, 36])
In [3]:
np.sqrt(numbers)
Out[3]:
array([1., 2., 3., 4., 5., 6.])
  • Add two arrays with the same shape, using the add universal function
  • Equivalent to:
    numbers + numbers2
In [4]:
numbers2 = np.arange(1, 7) * 10
In [5]:
numbers2
Out[5]:
array([10, 20, 30, 40, 50, 60])
In [6]:
np.add(numbers, numbers2)
Out[6]:
array([11, 24, 39, 56, 75, 96])

Broadcasting with Universal Functions

  • Universal functions can use broadcasting, just like NumPy array operators
In [7]:
np.multiply(numbers2, 5)
Out[7]:
array([ 50, 100, 150, 200, 250, 300])
In [8]:
numbers3 = numbers2.reshape(2, 3)
In [9]:
numbers3
Out[9]:
array([[10, 20, 30],
       [40, 50, 60]])
In [10]:
numbers4 = np.array([2, 4, 6])
In [11]:
np.multiply(numbers3, numbers4)
Out[11]:
array([[ 20,  80, 180],
       [ 80, 200, 360]])

Other Universal Functions

NumPy universal functions
Math — add, subtract, multiply, divide, remainder, exp, log, sqrt, power, and more.
Trigonometry —sin, cos, tan, hypot, arcsin, arccos, arctan, and more.
Bit manipulation —bitwise_and, bitwise_or, bitwise_xor, invert, left_shift and right_shift.
Comparison —greater, greater_equal, less, less_equal, equal, not_equal, logical_and, logical_or, logical_xor, logical_not, minimum, maximum, and more.
Floating point —floor, ceil, isinf, isnan, fabs, trunc, and more.

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