x = raw_input("Write a number")
if x.isalpha():
print "Invalid!"
elif x%2==0:
print "The number you have written is EVEN"
elif x%2!=0:
print "The number you have written is ODD"
else:
print "Invalid!"
It is supposed to check if the number is odd or even and print it out. My if statement checks if the raw_input was an alphabet because that won't work. And my elif statements check for odd or even.
The return value of raw_input is always a string. You'll need to convert it to an integer if you want to use the % operator on it:
x = raw_input("Write a number")
if x.isalpha():
print "Invalid!"
x = int(x)
Instead of x.isalpha() you can use exception handling instead:
try:
x = int(raw_input("Write a number"))
except ValueError:
print 'Invalid!'
else:
if x % 2 == 0:
print "The number you have written is EVEN"
else:
print "The number you have written is ODD"
because int() will raise ValueError if the input is not a valid integer.
try, execpt, finally and others at this stage. I am saying this because I am pretty new too... And using raw_input is one of the building blocks in most of the books/tutorials... :)
The return value of raw_input is a string, but you need a number to do the parity test.
You can check whether it's an alpha string, and if not, convert it to an int.
For example:
xs = raw_input("Write a number")
if xs.isalpha():
print "Invalid!"
else:
xn = int(xs)
if xn % 2 == 0:
print "The number you have written is EVEN"
elif xn % 2 != 0:
print "The number you have written is ODD"
else:
print "The universe is about to end."
