[python] TypeError: 'dict' object is not callable

I'm trying to loop over elements of an input string, and get them from a dictionary. What am I doing wrong?

number_map = { 1: -3, 2: -2, 3: -1, 4: 1, 5: 2, 6: 3 }
input_str = raw_input("Enter something: ")
strikes = [number_map(int(x)) for x in input_str.split()]

strikes  = [number_map(int(x)) for x in input_str.split()]
TypeError: 'dict' object is not callable

You need to use:

number_map[int(x)]

Note the square brackets!

Access the dictionary with square brackets.

strikes = [number_map[int(x)] for x in input_str.split()]

it's number_map[int(x)], you tried to actually call the map with one argument

strikes  = [number_map[int(x)] for x in input_str.split()]

You get an element from a dict using these [] brackets, not these ().

You need to use [] to access elements of a dictionary. Not ()

  number_map = { 1: -3, 2: -2, 3: -1, 4: 1, 5: 2, 6: 3 }
input_str = raw_input("Enter something: ")
strikes = [number_map[int(x)] for x in input_str ]

strikes  = [number_map[int(x)] for x in input_str.split()]

Use square brackets to explore dictionaries.

The syntax for accessing a dict given a key is number_map[int(x)]. number_map(int(x)) would actually be a function call but since number_map is not a callable, an exception is raised.

A more functional approach would be by using dict.get

input_nums = [int(in_str) for in_str in input_str.split())
strikes = list(map(number_map.get, input_nums.split()))

One can observe that the conversion is a little clumsy, better would be to use the abstraction of function composition:

def compose2(f, g):
    return lambda x: f(g(x))

strikes = list(map(compose2(number_map.get, int), input_str.split()))

Example:

list(map(compose2(number_map.get, int), ["1", "2", "7"]))
Out[29]: [-3, -2, None]

Obviously in Python 3 you would avoid the explicit conversion to a list. A more general approach for function composition in Python can be found here.

(Remark: I came here from the Design of Computer Programs Udacity class, to write:)

def word_score(word):
    "The sum of the individual letter point scores for this word."
    return sum(map(POINTS.get, word))