Adding not existing key to dictionary with if statement (Python)

Question

I'd like to know, how I could check if a key already exists in a dictionary. I am using the following code:

my_dict = {};
my_list = ["one", "two", "three", "one"];
for i in my_list:
    if i in my_dict: 
        continue;
    else:
       my_dict[i] = 0;

but I'd like to use "NOT" operator in if statement to remove else operator from it.

ebeneditos · Accepted Answer · 2016-12-19 06:45:23Z

3

This should work:

my_dict = {}
my_list = ["one", "two", "three", "one"]
for i in my_list:
    if i not in my_dict:
       my_dict[i] = 0

Thus, it will only add the value if the key doesn't exist in the dictionary.

answered Dec 19, 2016 at 6:39

ebeneditos

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2 Comments

Thank you, it really helped me.

I tried to use "!" Operator in if statement and it didn't work, I forgot about operator "not" :((.

Harsha Biyani · Accepted Answer · 2016-12-19 06:36:55Z

2

You can try:

if i not in my_dict:
    ....

answered Dec 19, 2016 at 6:36

Harsha Biyani

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PaulMcG · Accepted Answer · 2016-12-19 07:10:34Z

2

my_dict = dict.fromkeys(my_list, 0)

answered Dec 19, 2016 at 7:10

PaulMcG

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