How to use a variable in a dictionary before declaring it?

Question

To guess a user’s password I need to use each password in a loop:

for password in passwords_list:
    do_something_with_the_password({'Username': 'Joe', 'Password': password})

I get the dictionary {'Username': 'Joe', 'Password': password} from user input so need to use password variable before declaring it. I tried placeholders like password = None then declaring in the loop:

password = None
data = {'Username': 'Joe', 'Password': password}  ## Got from user input
for password in passwords_list:
     data['Password'] = password
     do_something_with_the_password(data)

The loop is huge and using multiprocessing accessing dictionary is troubling. I tried eval() but it significantly slowed my program. How to do this successfully?

data = {'Username': 'Joe', 'Password': password}
for password in passwords_list:
    do_something_with_the_password(data)  ## With it actually using the password, for that specific loop, in the dictionary

Asked By: LuckyCoder3607

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Source

Answer 1

If I understand what you’re asking correctly, you’re trying to dynamically set the key/value pairs of a dictionary in a for loop(?).

password_list = ["password", "password123"] # etc

# i.e. "Username"
key1 = input("First key")
# i.e. "Joe"
val1 = input("First val")
# i.e. "Password"
key2 = input("Second key")

for password in password_list:
    data = {key1: val1, key2: password}
    do_something(data)

Python will automatically insert "Username" for key1, "Joe" for val1, and "Password" for key2

Answered By: Leshawn Rice

How to use a variable in a dictionary before declaring it?

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