Logical Operations on String in Python

For strings in python, boolean operators (and, or, not) work. Let us consider the two strings namely str1 and str2 and try boolean operators on them: 

Python3

str1 = ''
str2 = 'geeks'

# repr is used to print the string along with the quotes

# Returns str1
print(repr(str1 and str2))

# Returns str1
print(repr(str2 and str1))

# Returns str2
print(repr(str1 or str2))

# Returns str2
print(repr(str2 or str1))

str1 = 'for'

# Returns str1
print(repr(str1 and str2))

# Returns str1
print(repr(str2 and str1))

# Returns str1
print(repr(str1 or str2))

# Returns str2
print(repr(str2 or str1))

str1='geeks'

# Returns False
print(repr(not str1))

str1 = ''

# Returns True
print(repr(not str1))


# Coded by Nikhil Kumar Singh(nickzuck_007)

Output:

''
''
'geeks'
'geeks'
'geeks'
'for'
'for'
'geeks'
False
True

Time Complexity: O(1) 
Auxiliary Space: O(1)

The output of the boolean operations between the strings depends on the following things: 

1. Python considers empty strings as having a boolean value of the ‘false’ and non-empty strings as having a boolean value of ‘true’.
2. For the ‘and’ operator if the left value is true, then the right value is checked and returned. If the left value is false, then it is returned
3. For the ‘or’ operator if the left value is true, then it is returned, otherwise, if the left value is false, then the right value is returned.

Note that the bitwise operators (|, &) don’t work for strings.