How to Convert Bool (True/False) to a String in Python?

by

💬 Question: Given a Boolean value True or False. How to convert it to a string "True" or "False" in Python?

Note that this tutorial doesn’t concern “concatenating a Boolean to a string”. If you want to do this, check out our in-depth article on the Finxter blog.

Simple Bool to String Conversion

To convert a given Boolean value to a string in Python, use the str(boolean) function and pass the Boolean value into it. This converts Boolean True to string "True" and Boolean False to string "False".

Here’s a minimal example:

>>> str(True)
'True'
>>> str(False)
'False'

Python Boolean Type is Integer

Booleans are represented by integers in Python, i.e., bool is a subclass of int. Boolean value True is represented with integer 1. And Boolean value False is represented with integer 0.

Here’s a minimal example:

>>> True == 1
True
>>> False == 0
True

Convert True to ‘1’ and False to ‘0’

To convert a Boolean value to a string '1' or '0', use the expression str(int(boolean)). For instance, str(int(True)) returns '1' and str(int(False)) returns '0'. This is because of Python’s use of integers to represent Boolean values.

Here’s a minimal example:

>>> str(int(True))
'1'
>>> str(int(False))
'0'

Convert List of Boolean to List of Strings

To convert a Boolean to a string list, use the list comprehension expression [str(x) for x in my_bools] assuming the Boolean list is stored in variable my_bools. This converts each Boolean x to a string using the built-in str() function and repeats it for all x in the Boolean list.

Here’s a simple example:

my_bools = [True, True, False, False, True]
my_strings = [str(x) for x in my_bools]
print(my_strings)
# ['True', 'True', 'False', 'False', 'True']

Convert String Back to Boolean

What if you want to convert the string representation 'True' and 'False' (or: '1' and '0') back to the Boolean representation True and False?

👉 Recommended Tutorial: String to Boolean Conversion

Here’s the short summary:

You can convert a string value s to a Boolean value using the Python function bool(s).

For example, bool('True') and bool('1') return True.

However, bool('False') and bool('0') return False as well which may come unexpected to you.

💡 This is because all Python objects are “truthy”, i.e., they have an associated Boolean value. As a rule of thumb: empty values return Boolean True and non-empty values return Boolean False. So, only bool('') on the empty string '' returns False. All other strings return True!

You can see this in the following example:

>>> bool('True')
True
>>> bool('1')
True
>>> bool('2')
True
>>> bool('False')
True
>>> bool('0')
True
>>> bool('')
False

Okay, what to do about it?

Easy – first pass the string into the eval() function and then pass the result into the bool() function. In other words, the expression bool(eval(my_string)) converts a string to a Boolean mapping 'True' and '1' to Boolean True and 'False' and '0' to Boolean False.

Finally – this behavior is as expected by many coders just starting out.

Here’s an example:

>>> bool(eval('False'))
False
>>> bool(eval('0'))
False
>>> bool(eval('True'))
True
>>> bool(eval('1'))
True

Feel free to go over our detailed guide on the function:

👉 Recommended Tutorial: Python eval() deep dive