Question

I want to check if an input value is equal a value inside the list without going through every value inside the list.

list=('a','b','c','d')
test=raw_input('enter letter')
if test in list:
   if test == a:
         (code)
   if test == b:
         (code)
   if test == c:
         (code)
   if test == d:
         (code)

Answer 1

This is better done with a dictionary.

def a_code():
    print "a"
def b_code():
    print "b"

d={'a':a_code,'b':b_code}
test=raw_input("enter a or b")
d[test]()

Of course, if code is the same in each case, you could do:

if test in ('a', 'b', 'c', 'd'): #tuple
   do_something()

which is functionally equivalent to:

if test in ['a', 'b', 'c', 'd']: #list slower than tuple -- ('a', 'b', 'c', 'd')
   do_something()

or, more simply:

if test in 'abcd': # string
   do_something()