7 ways to generate float range in Python

Python, PythonBasic

In this post, we will learn about7 ways to generate float range in Python or Python generate random float numbers in range with code examples. In Python, we will learn this by using list comprehension, numpy library arange(), linespace(), Round() function, and many other techniques.

Problem with Python range() function

The Python range() function takes three arguments, start, stop, and step integer arguments. If we pass a float number as an argument it throws a type error “TypeError: ‘float’ object cannot be interpreted as an integer”. Let us understand with an example.

start = 5
stop = 7.5
step = 0.3

for val in range(start, stop, step):
    print (val)

Output

TypeError: 'float' object cannot be interpreted as an integer

1. list comprehension to generate float range in Python

In this example, we are using the List comprehension with range() function to generate a range of float numbers.

Python Program to generate float range 

start = 3
stop = 30
step = 3


print("range of float number :")
[print(val /10.0, end=", ") for val in range(start, stop, step)]

Output

range of float number :
0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7,

2. map() with Lamda to generate float range in Python

In this code example, we are using the map() and lambda function to generate a range of float numbers.

Python Program to generate float range map() 

print(list(map(lambda val: val/10.0, range(5, 50, 10))))


result_list = list(map(lambda val: val/10.0, range(5, 50, 10)))

for num in result_list:
    print(num,end=",")

Output

[0.5, 1.5, 2.5, 3.5, 4.5]
0.5,1.5,2.5,3.5,4.5,

3. Round() function to generate float range in Python

Here, we are using Python’s built-in round() function to generate a range of float numbers.

Program Example

print("range of float number 1 to 10:")

[print(round(val* 0.10,2),end=", ") for val in range(1,10)]

Output

range of float number 0 to 10:
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,

4. Numpy arange() function to generate float range in Python

As we can’t pass float type arguments to Python built-in function arange() whereas in Numpy arrange() function we can pass float number to start, stop, step arguments and it returns sequence range of floating number.

  • To use Numpy we need to install it using the following command pip install numpy.
  • Import the numpy module in our program using the code import numpy as np

Python Program float range of positive number

import numpy as np

#range of float number using Numpy.arange()

for num in np.arange(2.5, 27.5, 2.5):
    print(num, end=', ')

Output

As we can see in the result it generated the float number from 2.5 to 25.0. It does not include the last value of 27.5 in the result because it never includes the stop value in the result.

2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, 20.0, 22.5, 25.0,

Python Program to Generate Range of float negative number

In the above example, we are generating the positive range of float numbers. Sometimes instead of positive, we need to generate a negative range of float numbers.

import numpy as np

#range of negative float number using Numpy.arange()

for num in np.arange(-2.5, -25.5, -2.5):
    print(num, end=', ')

Output

-2.5, -5.0, -7.5, -10.0, -12.5, -15.0, -17.5, -20.0, -22.5, -25.0,

Python Program to Pass float value in step parameter

We can pass the float step to np. arange() to generate a range of floating numbers.

import numpy as np

for num in np.arange(5, 20, 2.5):
    print(num, end=', ')

Output

5.0, 7.5, 10.0, 12.5, 15.0, 17.5,

5. Numpy linespace() to generate float range in Python

By using the Numpy modules, linespace() function we can generate the range of float numbers.

Syntax

np.linspace(start,stop,count,enpoint)

Parameters :

  • start : Starting value of sequence.
  • stop: Optionlal End value of the sequence,default value is 50.
  • num:The number of value to generate within given range.
  • endpoint : If true end value of stop parmeter will be include in last value of sequnce else it will not.The default value of it is 0.

Python Example 

import numpy as np
 

print(np.linspace(2.0, 10.0, num = 5))
print(np.linspace(4,24,num = 5, endpoint = False))

Output

[ 2.  4.  6.  8. 10.]
[ 4.  8. 12. 16. 20.]

6.itertool Module to generate a range of float number

The itertool Module isslice() method can be used to generate a floating-point range.We have to import this into the program to use it.

Program Example

import itertools
import math


def sequence(start, end, step):
    if step == 0:
        raise ValueError("step must be greater than 0")

    stop = math.ceil(abs(end - start) / step)
    
    return itertools.islice(itertools.count(start, step), stop)


for val in sequence(0, 5, 0.5):
    print(val, end=", ")

Output

0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5,

7. yield generator to generate a range of float number

In this example, we are using the decimal module along with the yield generator to generate a range of float.

Example

import decimal

def generate_float_range(startval, stopval, step):
  while startval < stopval:
    yield float(stopval)
    startval += decimal.Decimal(step)

print(list(generate_float_range(0, 5, 0.5)))

Output

[0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5]

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