In this article we will discuss how to create a Numpy array of evenly spaced numbers over a given interval using numpy.arrange().
numpy.arrange()
Python’s numpy module provides a function to create an Numpy Array of evenly space elements within a given interval i.e.
numpy.arange([start, ]stop, [step, ]dtype=None)
Arguments:
- start : It’s the start value of range.
- It’s optional, if not provided default value be 0.
- stop : End Value of range, array.
- It doesn’t include this value but it’s an end marker
- step : Spacing between two adjacent values.
- It’s optional, if not provided default value be 1.
- dtype : Data type of elements.
- If not provided will be deduced from other arguments.
This function returns an evenly spaced array of numbers from range start to stop -1 with equal intervals of step.
To use Numpy in our code we need to import following module i.e.
import numpy as np
Checkout some examples,
Example 1:
Create a Numpy Array containing numbers from 5 to 30 but at equal interval of 2
Here, start of Interval is 5, Stop is 30 and Step is 2 i.e.
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import numpy as np # Start = 5, Stop = 30, Step Size = 2 arr = np.arange(5, 30, 2) print(arr)
It will return a Numpy array with following contents,
[ 5 7 9 11 13 15 17 19 21 23 25 27 29]
Example 2:
Create a Numpy Array containing elements from 1 to 10 with default interval i.e. 1
As step argument is option, so when it is not provided then it’s default value will be 1. Let’s create a Numpy array from where start of interval is 5, Stop of interval is 30 and step size is default i.e 1 ,
import numpy as np # Start = 1, Stop = 10. As Step Size is not provided, so default value be 1 arr = np.arange(1, 10) print(arr)
It will return a Numpy array with following contents,
[1 2 3 4 5 6 7 8 9]
Example 3:
Create a Numpy Array containing elements up to 20 with default start and step size
As start & step arguments are optional, so when we don’t provide these arguments then there default value will be 0 & 1.
Let’s create a Numpy array with default start & step arguments, stop of interval is 20 i.e.
import numpy as np # Stop = 20. As Start and Step Size is not provided, so default value be 0 and 1 respectively arr = np.arange(20) print(arr)
It will return a Numpy array with following contents,
[ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19]
Complete example is as follows,
import numpy as np def main(): print('*** Create numpy array using numpy.arange() ***') print('Create a Numpy Array containing elements from 5 to 30 but at equal interval of 2') # Start = 5, Stop = 30, Step Size = 2 arr = np.arange(5, 30, 2) print('Contents of the Array : ', arr) print('Create a Numpy Array containing elements from 1 to 10 with default interval i.e. 1') # Start = 1, Stop = 10. As Step Size is not provided, so default value be 1 arr = np.arange(1, 10) print('Contents of the Array : ', arr) print('Create a Numpy Array containing elements up to 10 with default start and default step size') # Stop = 20. As Start & Step Size is not provided, so default value be 0 & 1 respectively arr = np.arange(20) print('Contents of the Array : ', arr) if __name__ == '__main__': main()
Output:
*** Create numpy array using numpy.arange() *** Create a Numpy Array containing elements from 5 to 30 but at equal interval of 2 Contents of the Array : [ 5 7 9 11 13 15 17 19 21 23 25 27 29] Create a Numpy Array containing elements from 1 to 10 with default interval i.e. 1 Contents of the Array : [1 2 3 4 5 6 7 8 9] Create a Numpy Array containing elements up to 10 with default start and default step size Contents of the Array : [ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19]