TypeError: 'dict' object is not callable
PythonDictionaryPython Problem Overview
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
Python Solutions
Solution 1 - Python
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.
Solution 2 - Python
Access the dictionary with square brackets.
strikes = [number_map[int(x)] for x in input_str.split()]
Solution 3 - Python
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 ]
Solution 4 - Python
strikes = [number_map[int(x)] for x in input_str.split()]
You get an element from a dict using these [] brackets, not these ().
Solution 5 - Python
strikes = [number_map[int(x)] for x in input_str.split()]
Use square brackets to explore dictionaries.
Solution 6 - Python
You need to use:
number_map[int(x)]
Note the square brackets!
Solution 7 - Python
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))
Solution 8 - Python
it's number_map[int(x)], you tried to actually call the map with one argument