python if user input contains string

Question

Very basic question. We have the code:

a = input("how old are you")

if a == string:
    do this

if a == integer (a != string):  
    do that

Obviously it doesn't work that way. But what is the easiest way to do this. Thanks for any answers in advance.

We could also say:

if string in a:
    do this

Answer 1

You can use str.isdigit and str.isalpha:

if a.isalpha():
   #do something
elif a.isdigit():
   #do something

help on str.isdigit:

>>> print str.isdigit.__doc__
S.isdigit() -> bool

Return True if all characters in S are digits
and there is at least one character in S, False otherwise.

help on str.isalpha:

>>> print str.isalpha.__doc__
S.isalpha() -> bool

Return True if all characters in S are alphabetic
and there is at least one character in S, False otherwise.

Answer 2

You can use a.isalpha(), a.isdigit(), a.isalnum() to check if a is composed of letters, numbers, or a combination of numbers and letters, respectively.

if a.isalpha(): # a is made up of only letters
    do this

if a.isdigit(): # a is made up of only numbers
    do this

if a.isalnum(): # a is made up numbers and letters
    do this

The Python docs will tell you in more detail the methods you can call on strings.