What does .update() do, and why? [duplicate]

Question

I wanted to learn more of python and came to the command ".update()". I googled it up and really tried to understood, however it's randomized.

x = {"apple", "banana", "cherry"}
y = {"google", "microsoft", "apple"}

x.update(y) 

print(x)

this is my code and there are 2 things I could see:

1. The output gives me 5 words and somehow just one is missing
2. The words are getting chosen randomly

Did I do something wrong? Why is there just one word missing and not 2/3/4?

Answer 1

x and y are the sets. Set is a type of data structure that keeps only unique values. So, when you update x with y, x set will contain unique values from both sets.