Python String lower() method converts a string object into a lower case string. This is one of the builtin string functions in Python. Since strings are immutable in Python, this method only returns a copy of the original string.
Syntax and Usage of Python String lower() Method
Format:
str_copy = str_orig.lower()
Here, str_copy
is the lowercase string of str_orig
.
a = "HELLO FROM ASKPYTHON"
b = a.lower()
print(a)
print(b)
Output
HELLO FROM ASKPYTHON
hello from askpython
This will make the entire output string lowercase, even if only a part of the input string was uppercase.
a = "Hello from AskPython"
b = a.lower()
print(a)
print(b)
Output
Hello from AskPython
hello from askpython
Since any string literal is handled as a Unicode by Python3, it can lowercase different languages too.
>>> string = 'Километр'
>>> string
'Километр'
>>> string.lower()
'километр'
Pandas module – lower()
There is a lower()
method in the Pandas module as well, which has the same functionality as the native Python method, but is for Pandas Objects.
Format:
pandas_copy = pandas_object.str.lower()
Here is an example illustrating the same:
>>> import pandas as pd
>>>
>>> s = pd.Series(['Hello', 'from', 'ASKPYTHON'])
>>> print(s)
0 Hello
1 from
2 ASKPYTHON
dtype: object
>>>
>>> print(s.str.lower())
0 hello
1 from
2 askpython
dtype: object
>>> print(s)
0 Hello
1 from
2 ASKPYTHON
dtype: object
As you can observe, the original object remains unchanged, and we get a new object with all lowercase strings!
References
- Python Documentation on
str.lower()
- StackOverflow Question