print "This is a program to help give you an idea which programming languages you should consider learning."
print "While there are any number of languages you might consider, this program considers only 11 of the most" 
print "popluar ones. The program will ask you to input a ranking or weighting for a number of criteria" 
print "that may be of importance in choosing your next programming language."

def get_list(heading, prompt):
        """ get_list(heading, prompt) -> list

This function prompts for a list of things.  The heading is printed on
a line by itself, and the prompt must have a %d substitution for the
number of the item within the list.
"""
        print heading
        print
        print "(enter a blank line to end the list)"
        ret = []
        i = 1
        while 1:
                line = raw_input(prompt % i)
                if not line:
                        break
                ret.append(line)
                i=i+1
        print
        return ret

def get_number(prompt):
        """ get_number(prompt) -> float

This function prompts for a number.  If the user enters bad input, such as
"cat" or "3l", it will prompt again.
"""
        res = None
        while res is None:
                try:
                        res = float(raw_input(prompt))
                except ValueError: pass
        return res


options = ["Python", "Perl", "Ruby", "Tcl", "JavaScript", "Visual Basic", "Java", "C++", "C", "Lisp", "Delphi"]
criteria = ["ease of learning", "ease of use", "speed of program execution", "quality of available tools", "popularity", "power & expressiveness", "cross platform?", "cost"]


rankings = {}
print
print "Enter relative importance of criteria (higher is more important)"
print
for c in criteria:
                rankings[c] = get_number("Criterion %s: " % c)

# Next, get the user to score each option on all the criteria.
# Here, we index the dictionary on the pair (option, criterion). 
# This is similar to a two-dimensional array in other languages

score = {("Python", "ease of learning"):100, ("Python", "ease of use"):100, ("Python", "speed of program execution"):10, ("Python", "quality of available tools"):70, ("Python", "popularity"):50, ("Python", "power & expressiveness"):100, ("Python", "cross platform?"):100, ("Python", "cost"):100,
("Perl", "ease of learning"):50, ("Perl", "ease of use"):90, ("Perl", "speed of program execution"):30, ("Perl", "quality of available tools"):50, ("Perl", "popularity"):75, ("Perl", "power & expressiveness"):100, ("Perl", "cross platform?"):100, ("Perl", "cost"):100,
("Ruby", "ease of learning"):50, ("Ruby", "ease of use"):100, ("Ruby", "speed of program execution"):20, ("Ruby", "quality of available tools"):20, ("Ruby", "popularity"):10, ("Ruby", "power & expressiveness"):100, ("Ruby", "cross platform?"):80, ("Ruby", "cost"):100, 
("Tcl", "ease of learning"):100, ("Tcl", "ease of use"):100, ("Tcl", "speed of program execution"):10, ("Tcl", "quality of available tools"):50, ("Tcl", "popularity"):40, ("Tcl", "power & expressiveness"):10, ("Tcl", "cross platform?"):100, ("Tcl", "cost"):100,
("JavaScript", "ease of learning"):70, ("JavaScript", "ease of use"):75, ("JavaScript", "speed of program execution"):10, ("JavaScript", "quality of available tools"):50, ("JavaScript", "popularity"):100, ("JavaScript", "power & expressiveness"):40, ("JavaScript", "cross platform?"):50, ("JavaScript", "cost"):100, 
("Visual Basic", "ease of learning"):50, ("Visual Basic", "ease of use"):100, ("Visual Basic", "speed of program execution"):20, ("Visual Basic", "quality of available tools"):100, ("Visual Basic", "popularity"):100, ("Visual Basic", "power & expressiveness"):50, ("Visual Basic", "cross platform?"):1, ("Visual Basic", "cost"):1,
("Java", "ease of learning"):15, ("Java", "ease of use"):50, ("Java", "speed of program execution"):50, ("Java", "quality of available tools"):100, ("Java", "popularity"):100, ("Java", "power & expressiveness"):100, ("Java", "cross platform?"):100, ("Java", "cost"):100,
("C++", "ease of learning"):10, ("C++", "ease of use"):25, ("C++", "speed of program execution"):90, ("C++", "quality of available tools"):100, ("C++", "popularity"):100, ("C++", "power & expressiveness"):100, ("C++", "cross platform?"):100, ("C++", "cost"):100,
("C", "ease of learning"):15, ("C", "ease of use"):10, ("C", "speed of program execution"):100, ("C", "quality of available tools"):100, ("C", "popularity"):100, ("C", "power & expressiveness"):100, ("C", "cross platform?"):110, ("C", "cost"):100,
("Lisp", "ease of learning"):20, ("Lisp", "ease of use"):30, ("Lisp", "speed of program execution"):70, ("Lisp", "quality of available tools"):50, ("Lisp", "popularity"):25, ("Lisp", "power & expressiveness"):110, ("Lisp", "cross platform?"):80, ("Lisp", "cost"):90,
("Delphi", "ease of learning"):50, ("Delphi", "ease of use"):110, ("Delphi", "speed of program execution"):85, ("Delphi", "quality of available tools"):100, ("Delphi", "popularity"):30, ("Delphi", "power & expressiveness"):100, ("Delphi", "cross platform?"):80, ("Delphi", "cost"):10}


# Calculate the resulting score for each option.  
# The "result" dictionary is indexed with the names of the options.
result = {}
for o in options:
        value = 0
        for c in criteria:
                
                value = value + rankings[c] * score[o, c]
        result[o] = value

# Now, I want to take the dictionary result, and turn it into a ranked list

results = result.items()        # A list of tuples (key, value)
results.sort(lambda x, y: -cmp(x[1], y[1]))
                                # Sort the list using the reverse of the
                                # "value" of the entry, so that higher
                                # values come first

print
print "Results, in order from highest to lowest score"
print
print "%5s %s" % ("Score", "Option")

# Take the pairs out of results in order, and print them out
for option, result in results:
        print "%5s %s" % (result, option)