访问字典中的值

Question

there are no problems with the code - it is running just fine, however, I'm not fully understanding why it is working.

From my understanding, if I provide only 1 variable in the for loop - it automatically stores "keys" of the dictionary (which it did in the 1st print statement). My question is, how come the last print statement " + favorite_languages[name].title() + "!") -- prints the actual values?

Were the keys not stored in "name" in the for loop? I'm reading the code and to me it reads - Hey phil, I see your favorite language is phil!

Could anyone explain?

favorite_languages = {
 'jen': 'python',
 'sarah': 'c',
 'edward': 'ruby',
 'phil': 'python',
 }


friends = ['phil', 'sarah']
for name in favorite_languages:
 print(name.title())
 if name in friends:
     print("Hi " + name.title() + ", I see your favorite language is " + favorite_languages[name].title() + "!")

Answer 1

Dictionaries work like this:

{ KEY : VALUE }

In the example

{'Phil':'python'}

Phil is the key, and not a value. so accessing ['Phil'] outputs the value associated with that key which isn't 'Phil' but 'python'.

I think you are confused because implicitly you expected a format more like this:

favorite_languages = (
{name: 'Phil', language: 'Python'},
{name: 'sarah', language: 'c'}
)

Which is a list of dicts!

Answer 2

Name is the key for the dictionary

favorite_languages = {
 'jen': 'python',
 'sarah': 'c',
 'edward': 'ruby',
 'phil': 'python',
 }

On which you are iterating. If you execute a print in the foor loop you'll see what name is:

for name in favorite_languages:
    print(name.title())
    if name in friends:
        print(name) # here
        print("Hi " + name.title() + ", I see your favorite language is " + favorite_languages[name].title() + "!")

To understand better, try to execute this code:

for key, value in favorite_languages.items():
    print("This is the key {}. This is the value {}".format(key, value))

# This is the key jen. This is the value python
# This is the key sarah. This is the value c
# This is the key edward. This is the value ruby
# This is the key phil. This is the value python