Dictionary - 'str' object is not callable [closed]

问题

I am new to Python and trying to create a user interface with options to insert, delete and update data. THe data will be manipulated in a text file. I wanted to accept option from user and call respective function to do the activity. One alternative that I found was to declare Dictionary The whole code is :

print("Select options from below")
dict_options = {'1' : 'Insert', 
                '2' : 'Update', 
                '3' : 'Delete',
                '4' : 'Display_number_of_records', 
                '5' : 'Display_all_records', 
                '6' : 'Exit'}



for key in dict_options.keys():
    value = dict_options.get(key)
    print(str(key) + ". " + value)


option = input("Enter an option : ")

while (option != '6'):
    value = dict_options.get(option)
    dict_options[option]()
option = input("Enter an option : ")


def Insert():
    print("Insert a record")
    return`enter code here`

When I execute, it gives me an error:

TypeError: 'str' object is not callable at dict_options[option]()

回答1:

Strings, such as dict_options[option], are not callable, but functions are. Therefore, make the dict_options values be function objects: Change

dict_options = {'1' : 'Insert', 
                '2' : 'Update', 
                '3' : 'Delete',
                '4' : 'Display_number_of_records', 
                '5' : 'Display_all_records', 
                '6' : 'Exit'}

dict_options = {'1' : Insert, 
                '2' : Update, 
                '3' : Delete,
                '4' : Display_number_of_records, 
                '5' : Display_all_records, 
                '6' : Exit}

Note you'll have to define the functions before defining dict_options.

Also, to print the name of the function, change value to value.__name__:

for key in dict_options.keys():
    value = dict_options.get(key)
    print(str(key) + ". " + value)

becomes

for key in dict_options.keys():
    value = dict_options.get(key)
    print(str(key) + ". " + value.__name__)

回答2:

EDIT: Looks like unutbu beat me to it.

This line:

dict_options[option]()

Evaluates to something like this:

'Some String'()

You cannot call a string like this (try it!). You'll have to edit your dictionary so the values inside are functions (or some other kind of callable object), not strings.

EDIT:

Assuming the string values in your dictionary are the names of callable objects (e.g. functions), you COULD make it work the way you have it using exec:

exec(dict_options[option] + '()')

However, this is BAD BAD! Do NOT do this!

来源：https://stackoverflow.com/questions/27742714/dictionary-str-object-is-not-callable

标签

python-3.x