I have a program that asks the user's name:
while True:
try:
name = str(input("Please enter your name > "))
except ValueError:
print("Please enter a valid name")
continue
else:
break
I want to prevent the user from entering an integer, but with the code above integers are accepted in a string. How can I prevent the user from entering an integer in the string?
Firstly, do not cast str as input returns an str. Note from the docs
The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that
After you get the input into name you can have a if condition.
name = str(input("Please enter your name > "))
if (re.search('\d',name)):
print("Sorry your name contains a number")
And don't forget to import re
break when trying to cast to an int if an exception is raised as it is not an int:
while True:
name = input("Please enter your name > ")
try:
int(name)
except ValueError:
break
print("Please enter a valid name")
str.digit might work also but will fail on negative input.
To check if any character is a digit use any:
while True:
name = input("Please enter your name > ")
if any(ch.isdigit() for ch in name):
print("Please enter a valid name")
else:
break
You could also create a set of accepted characters:
from string import ascii_letters
st = set(ascii_letters)
while True:
name = input("Please enter your name > ")
if not st.issuperset(name):
print("Please enter a valid name")
else:
break
Where you might want to add -, " " and any other potential characters.
try
str.isalpha.foo-bar is a valid name as is Lord foobarYou can use the string method isdigit() to check if the string is just integers.
name = input("Please enter your name: ")
if name.isdigit() == True:
print ("That's not a name!")
Likewise, you can also use the method isalpha() to check if the string is just text. However, if there's a space, it will return False.
name = input("Enter your name: ")
if name.isalpha() != True:
print ("That's not a name!")
if name.isdigit() will do but -100 is a digit and if not name.isalpha() will also be sufficient
isalpha() is that some names contain punctuation characters, like a dash.
Maybe:
if len(set(name) - set('1234567890')) < len(set(name)):
name = input("Please enter a valid name: ")