float() in Python | Python float() Function

Overview

In Python Programming, float() is an inbuilt function that converts an integer or specific strings into floating-point values.

Syntax of float() function in Python

Parameters of float() function in Python

It accepts only one parameter but it's optional:

x (Optional) - number or string that needs to be converted to floating point number If it's a string, the string should contain decimal points.

Return values of float() function in Python

Argument type	Input	Return value	Output
No argument is passed	-	0.0	0.0
Integer	4	Floating point number	4.0
Floating point number	30.0	Floating point number	30.0
String	"20"	Floating point number	20.0
String	"nan", "NaN"	nan	nan
String	"inf", "InF", "InFiNiTy", "infinity"	inf	inf
String	"Scaler"	ValueError: could not convert string to float : 'Scaler'	-

Example of float() function in Python

Let's look at an example to convert string 30 to floating-point value 30.0:

Code:

Output

What is float() function in Python?

In all programming languages, typecasting of the data has been a important feature.

Python provides us an inbuilt function to convert integers and few strings to floating point numbers. Let's see how float in Python works with different parameters:

If no argument is passed then 0.0 is returned.
If any number is passed, then floating point number is returned.
If a string is passed which is not a decimal point number or strings mentioned above, then ValueError is raised.
If a number passed is outside the range of Python float() then OverflowError is generated.

More Examples

Example 1: How float() works in Python?

Python code to explain the working of the float() in Python.

Code:

Output:

Explanation:

The last string passed does not have a decimal point number hence the code returns ValueError.

Example 2: Converting a string into a floating-point number

Code:

Output:

Explanation:

The string passed into the float() in the Python program contains integers and hence the program returns the required floating-point value.

Example 3: Using float() with infinity and Nan(Not a number)

Code:

Output:

Only for the specified strings, the float() in Python returns the above output.

Example 4: Converting an Integer to a Float in Python

Code:

Output:

Explanation:

The above code represents when an integer is passed into the float function. The code will always return the required floating-point value in such cases.

Example 5: Python float() Exception

Code:

Output:

Explanation:

In the above code, a string is passed to the float() function to check if it is a decimal point value. But it turns out not to be, hence the code returns an error.

Conclusion

float() in Python is an inbuilt function that is used to convert any number or specific strings to a floating-point number.These specific strings are: "nan", "NaN", "inf", "InF", "InFiNiTy", "infinity".
If other strings are given as input then the code returns an error i.e., ValueError.