TypeError: can only concatenate str (not "NoneType") to str in Python
Dung Do Tien
Sep 19 2021
173
Hello you guys, I am a newbie in Python and I'm also studying more about Python.
I have a small code functions and I want to convert all uppercase characters to lowercase. Function as below:
def convertChar(char):
if char >= 'A' and char <= 'Z':
return chr(ord(char) + 32)
def toLowerCase(string):
for char in string:
string = string + convertChar(char)
return string
string = input("Enter string - ")
result = toLowerCase(string)
print(result)
But I get an exception TypeError: can only concatenate str (not "NoneType") to str when I run code above.
Enter string - Python
Traceback (most recent call last):
File "main.py", line 9, in <module>
result = toLowerCase(string)
File "main.py", line 6, in toLowerCase
string = string + convertChar(char)
TypeError: can only concatenate str (not "NoneType") to str
And I am using python 3.8.2
Anyone can explain it to me? How can I solve it?
Thanks for any response.
Have 1 answer(s) found.
-
K0
Kitajima 2910 Sep 19 2021
This error throw because your function is not return value. You can see
convertChar()function still not return forelsecase. So you can change code as below:def convertChar(char): if char >= 'A' and char <= 'Z': return chr(ord(char) + 32) return char def toLowerCase(string): str = "" for char in string: str = str + convertChar(char) return str string = input("Enter string - ") result = toLowerCase(string) print(result)In the
toLowerCase()function I also changed a little code, I used to other variable to help store value return for this function help avoid duplicate content, and below is result:Enter string - LAZY LOADING, AGGREGATE AND CQRS lazy loading, aggregate and cqrsI hope it resolve issue for you.
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