In this article, you will learn how to generate a range of floating-point numbers in Python.

The Python range() works only with integers. It doesn’t support the float type, i.e., we cannot use floating-point/decimal value in any of its arguments.

For example, If you use `range()`

with float step argument, you will get a `TypeError 'float' object cannot be interpreted as an integer`

.

```
for i in range(0, 1, 0.1):
print(i)
# Output TypeError: 'float' object cannot be interpreted as an integer
```

**Goals of this article** –

- Use NumPy’s
`arange()`

and`linspace()`

functions to use decimal numbers in a start, stop and step argument to produce a range of floating-point numbers. - Use Python generator to produce a range of float numbers
**without using any library**or module.

## Table of contents

## Range of floats using NumPy’s arange()

The NumPy library has various numeric and mathematical functions to operate on multi-dimensional arrays and matrices.

NumPy has the `arange()`

function to get the range of floating-point numbers. It has the same syntax and functionality as a Python built-in range() function. Also, it allows us to use floating-point numbers in the start, stop and step arguments.

Syntax of `np.arange()`

function

`np.arange (start, stop, step)`

Time needed: 5 minutes

How to generate a range of floats in Python

**Install numpy module**NumPy doesn’t come with default Python installation. You can install it using

`pip install numpy`

.**Import numpy module**Import numpy module using the

statement.**import**numpy**as**np**Use numpy.arange()**Pass float numbers to its start, stop, and step argument. For example,

`np.arange(0.5, 6.5, 1.5)`

will return the sequence of floating-point numbers starting from 0.5 up to 6.5.

**Example**

```
import numpy as np
# range for floats with np.arange()
for i in np.arange(0, 4.5, 0.5):
print(i, end=', ')
# Output 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0,
# Example 2
for i in np.arange(5.5, 15.5, 2.5):
print(i, end=' ')
# Output 5.5, 8.0, 10.5, 13.0,
```

**Note**: As you can see in the output, We got decimal numbers starting from 0.0 to 4.0. If you notice, `np.arange()`

didn’t include 4.5 in its result because it but **never includes the stop number in its result**. It stops before taking the last step.

**Also, see**: Python range() and for loop exercise.

### Use float number only in step argument

Let see how to use a floating-point step along with a start and stop integers in `np.arange()`

to generate floating-point numbers of a specific interval. In this example, the step value is 2.5.

```
import numpy as np
# float step
for i in np.arange(1, 10, 2.5):
print(i, end=', ')
# Output 1.0, 3.5, 6.0, 8.5
```

### Reverse float range

Use the `reversed()`

function to display the sequence of float numbers produced by a `np.arange()`

by descending order.

```
import numpy as np
# reverse range of floats
for i in reversed(np.arange(5.5, 30.5, 5.5)):
print(i, end=', ')
# Output 27.5, 22.0, 16.5, 11.0, 5.5,
```

### Range for negative float numbers

let’s see how to use all negative float numbers in `np.arange()`

.

```
import numpy as np
# Negative range of float numbers
for i in np.arange(-2.5, -20.5, -2.5):
print(i, end=', ')
# Output -2.5, -5.0, -7.5, -10.0, -12.5, -15.0, -17.5, -20.0,
```

## Range of floats using `numpy.linspace()`

Let’s see how to use a `np.linspace()`

to get a range of float numbers.

The `numpy.linspace()`

**returns number spaces evenly w.r.t interval**. Similar to `arange`

, but instead of step, it uses a sample number.

We need to define the **start** point and an **endpoint** of an interval, and then specify the total number of **samples** you want within that interval (including the start and the endpoint). The `numpy.linspace`

function will return a sequence of evenly spaced values on that interval

**Syntax**

`np.linspace(start, stop, num, endpoint)`

**Parameters**

`start`

: The starting position of the range, by default, starts with 0 if not specified.`stop`

: The end of the interval range.`num`

: The number of samples to generate, default is 50. It cannot be negative, i.e., The Total numbers you want in the output range.`endpoint`

: Set it to`False`

if you don’t’ want to include the stop value in the result.

**Example**

```
import numpy as np
# Float range using np.linspace()
# from 2.5 to 12.5
# num = total float numbers in the output
for i in np.linspace(2.5, 12.5, num=5):
print(i, end=', ')
# Output 2.5, 5.0, 7.5, 10.0, 12.5,
print('')
# endpoint=False to not include stop number in the result
for i in np.linspace(2.5, 12.5, num=5, endpoint=False):
print(i, end=', ')
# Output 2.5, 4.5, 6.5, 8.5, 10.5,
```

**Note**: The `numpy.linspace()`

returns number spaces evenly w.r.t interval. We cannot pass custom step value; instead, we can decide how many samples we want spaces evenly w.r.t interval.

## Range of floats using generator and yield

What to do if you don’t want to use the numpy library just for `arange()`

and `linspace()`

function?

In this case, you can use Python generators and yield to write a custom function to generate a range of float numbers.

You can define a generator to replicate the behavior of Python’s built-in function range() in such a way that it can accept floating-point numbers and produces a range of float numbers.

The following code divided into 2 Sections.

- The custom
function.`frange()`

- Another section tests custom
`frange()`

function using the floating-point number with the following approaches.- Positive float numbers in
`frange()`

arguments. - With negative float numbers in
`frange()`

arguments. - Both negative and positive float step in
`frange()`

arguments.

- Positive float numbers in

Now, l**et see the example**.

```
def frange(start, stop=None, step=None):
# if set start=0.0 and step = 1.0 if not specified
start = float(start)
if stop == None:
stop = start + 0.0
start = 0.0
if step == None:
step = 1.0
print("start = ", start, "stop = ", stop, "step = ", step)
count = 0
while True:
temp = float(start + count * step)
if step > 0 and temp >= stop:
break
elif step < 0 and temp <= stop:
break
yield temp
count += 1
for i in frange(1.5, 5.5, 0.5):
print("%g" % i, end=", ")
print('\n')
for i in frange(-0.1, -0.5, -0.1):
print("%g" % i, end=", ")
print('\n')
for num in frange(0.5, 0.1, -0.1):
print("%g" % num, end=", ")
print('\n')
for num in frange(0, 7.5):
print("%g" % num, end=", ")
print('\n')
for num in frange(2.5, 7.5):
print("%g" % num, end=", ")
print('\n')
```

**Output**:

start = 1.5 stop = 5.5 step = 0.5 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, start = -0.1 stop = -0.5 step = -0.1 -0.1, -0.2, -0.3, -0.4, start = 0.5 stop = 0.1 step = -0.1 0.5, 0.4, 0.3, 0.2, start = 0.0 stop = 7.5 step = 1.0 0, 1, 2, 3, 4, 5, 6, 7, start = 2.5 stop = 7.5 step = 1.0 2.5, 3.5, 4.5, 5.5, 6.5,

### Positive float number sequence using a generator

If you need a range of only positive float-numbers, you can try this code.

```
def frange_positve(start, stop=None, step=None):
if stop == None:
stop = start + 0.0
start = 0.0
if step == None:
step = 1.0
print("start = ", start, "stop = ", stop, "step = ", step)
count = 0
while True:
temp = float(start + count * step)
if temp >= stop:
break
yield temp
count += 1
for i in frange_positve(1.5, 10.5, 0.5):
print("%g" % i, end=", ")
# Output 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10,
```

### Negative float numbers sequence using a generator

If you need a range of only negative float-numbers, you can try this code.

```
def frange_negative(start, stop=None, step=None):
if stop == None:
stop = start + 0.0
start = 0.0
if step == None:
step = 1.0
print("start= ", start, "stop= ", stop, "step= ", step)
count = 0
while True:
temp = float(start + count * step)
if temp <= stop:
break
yield temp
count += 1
for i in frange_negative(-0.1, -0.5, -0.1):
print("%g" % i, end=", ")
# Output -0.1, -0.2, -0.3, -0.4,
```

**Output**:

Using Negative float number in range function start= -0.1 stop= -0.5 step= -0.1 -0.1, -0.2, -0.3, -0.4,

## Range of floats using a list comprehension

Let’s see how to use list comprehension to generate a range of float numbers from **0.5 to 9.5**.

Here we are using the range function to generate numbers and dividing each number by 10.0 to get a float number.

```
# range from 0.5 to 9.5 with step 0.5
# using list comprehension
[print(x / 10.0, end=", ") for x in range(5, 100, 5)]
# output 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5,
```

## Range of floats using a itertools

Let’s see how to generate floating-point range using a `itertools`

.

```
import itertools
def seq(start, end, step):
assert (step != 0)
sample_count = int(abs(end - start) / step)
return itertools.islice(itertools.count(start, step), sample_count)
for i in seq(0, 1, 0.1):
print("%g" % i, end=", ")
# Output 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,
```

## Next Steps

I want to hear from you. What do you think of this article on the Python float range? Do you have any better alternative to generate a range of float numbers in Python? let me know by leaving a comment below.

Also, try to solve the Python for loop and range() Exercise for a better understanding of Python’s range().