How to downcase the first character of a string?
PythonStringPython Problem Overview
There is a function to capitalize a string, I would like to be able to change the first character of a string to be sure it will be lowercase.
How can I do that in Python?
Python Solutions
Solution 1 - Python
One-liner which handles empty strings and None:
func = lambda s: s[:1].lower() + s[1:] if s else ''
>>> func(None)
>>> ''
>>> func('')
>>> ''
>>> func('MARTINEAU')
>>> 'mARTINEAU'
Solution 2 - Python
s = "Bobby tables"
s = s[0].lower() + s[1:]
Solution 3 - Python
def first_lower(s):
if len(s) == 0:
return s
else:
return s[0].lower() + s[1:]
print first_lower("HELLO") # Prints "hELLO"
print first_lower("") # Doesn't crash :-)
Solution 4 - Python
Interestingly, none of these answers does exactly the opposite of capitalize(). For example, capitalize('abC') returns Abc rather than AbC. If you want the opposite of capitalize(), you need something like:
def uncapitalize(s):
if len(s) > 0:
s = s[0].lower() + s[1:].upper()
return s
Solution 5 - Python
Simplest way:
>>> mystring = 'ABCDE'
>>> mystring[0].lower() + mystring[1:]
'aBCDE'
>>>
Update
See this answer (by @RichieHindle) for a more foolproof solution, including handling empty strings. That answer doesn't handle None though, so here is my take:
>>> def first_lower(s):
if not s: # Added to handle case where s == None
return
else:
return s[0].lower() + s[1:]
>>> first_lower(None)
>>> first_lower("HELLO")
'hELLO'
>>> first_lower("")
>>>
Solution 6 - Python
No need to handle special cases (and I think the symmetry is more Pythonic):
def uncapitalize(s):
return s[:1].lower() + s[1:].upper()
Solution 7 - Python
I'd write it this way:
def first_lower(s):
if s == "":
return s
return s[0].lower() + s[1:]
This has the (relative) merit that it will throw an error if you inadvertently pass it something that isn't a string, like None or an empty list.
Solution 8 - Python
This duplicate post lead me here.
If you've a list of strings like the one shown below
l = ['SentMessage', 'DeliverySucceeded', 'DeliveryFailed']
Then, to convert the first letter of all items in the list, you can use
l = [x[0].lower() + x[1:] for x in l]
Output
['sentMessage', 'deliverySucceeded', 'deliveryFailed']
Solution 9 - Python
pip install pydash first.
import pydash # pip install pydash
assert pydash.lower_first("WriteLine") == "writeLine"
https://github.com/dgilland/pydash