Iterating over dictionaries using for loops

Question

Here is the code:

d = {'x': 1, 'y': 2, 'z': 3} 
for key in d:
    print (key, 'corresponds to', d[key])

What I don't understand is the key portion. How does Python recognize that it needs only to read the key from the dictionary? Is key a special word in Python? Or is it simply a variable?

Answer 1

Here in this example the key is used as a variable, it is not a keyword.Since you have defined a dictionary, the syntax is {‘Key’ : ‘Value’} key and value pair separated by colon (:)
You can use other word instead of Key and the output will be the same

d = {'x': 1, 'y': 2, 'z': 3} 
for value in d:
    print( value, 'corresponds to', d[value])

Since Dictionary has keys and values that can be retrieved in Python using:

d.keys()

Output

dict_keys(['x', 'y', 'z'])

d.values()

Output

dict_values([1, 2, 3])