input in python to be only in string

Question

I am a beginner in Python so kindly do not use complex or advanced code.

I have three if conditions to which I want certain responses, and I want my code to give only one response.

1. First I want the input to only answer in string not in integer or float

   f = input("Please enter your name :")
   

2. it should give an error if an integer or float is given

   if type (f)== int or float :
       print("Invalid entry")
   

3. if f=="" :
       print("Invalid input. Your name cannot be blank. ")
   

I have already tried

f = str(input("Please enter your name :"))

it is not working my code still accepts the ans in integer and string.

If I give the string input it gives me the following response:

if type (f)== int or float :
    print("Invalid entry")

I am a beginner so I might have made a lot of mistakes. Your patience would be appreciated.

Answer 1

If you're using Python 3.X, input() always returns a string. Note that there are strings such as "1", which are still strings, despite the fact that they look a lot like numbers.

I think what you actually want is to verify that a string contains only alphabetical characters, in which case you could do:

s = input("Enter your name: ")
if not s.isalpha():
    print("Please enter only alphabetical characters for your name.")

Or perhaps you want to accept all strings except ones that are composed solely of digits.

s = input("Enter your name: ")
if s.isdigit():
    print("Your name cannot be a number.")

Or do you want to accept only strings that don't contain any digits at all?

s = input("Enter your name: ")
if any(char.isdigit() for char in s):
    print("Please do not include digits in your name.")

If you're using Python 2.7 or lower, input() can return a string, or an integer, or any other type of object. This is generally more of a headache than it's worth, so I recommend switching to raw_input(), at which point all of the advice above applies.

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Once you've got the right logic for your validation conditions, you might think "ok, but how do I get the program to go back to the first input() call so the user gets another chance to enter the right input?". If so, you may find this useful: Asking the user for input until they give a valid response

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PS. When it comes to names, be careful about how strictly you validate input. Err on the side of accepting unusual inputs. Otherwise you might get complaints from people with names like "John Smith the 3rd" or "Steve O'Reilley" or "田中太郎". Related reading: Falsehoods Programmers Believe About Names

Answer 2

input() always returns a string, so you can try these methods:

METHOD 1. Use isalpha(). It checks if all characters are alphabetical, but does not allow for spaces.

name = input('Please enter your name: ')
if name.isalpha() == False:
    print('Please enter a alphabetical name')

To allow spaces in a name (for example, first and last name), do this:

name = input('Please enter your name: ')
nospacename = name.replace(' ','')
if nospacename.isalpha() == False:
    print('Please enter a alphabetical name')

This does not change the value of name, however.

METHOD 2. Try to convert it to a integer or float, and print the message if it is possible. Otherwise, do nothing.

name = input('Please enter your name: ')
try:
    intname = int(name)
    floatname = float(name)
    print('Please enter an alphabetical name.')
except:
    pass

METHOD 3. Go through the name, character by character, and check if it is a type int (integer) or float.

name = input('Please enter your name: ')
namelist = list(name)
invalid = 0
for i in range(len(name)):
    if type(namelist[i]) == int:
        invalid = invalid + 1
    elif type(namelist[i]) == float:
        invalid = invalid + 1
    else:
        pass

if invalid > 0:
    print('Please enter a alphabetical name.')
    

Answer 3

Try this code:

def only_name():
    s = input("Enter your name: ")
    if not s.isalpha():
        print("It should not be number")
        only_name()
    else:
        print(s)

only_name()