Python dictionaries

Question

Hey everyone,

So I'm learning Python dictionaries and there's a little exercise that blocks me, written below:

primes = {1: 2, 2: 3, 4: 7, 7:17,}

print(primes[4]) # 7
print(primes[primes[1]]) # 3
print(primes[primes[4]]) # 17

The first one got it, it prints the 4th number on the list but the other ones can't understand why?
Tried different numbers and added even '9: 37' to see if the code checked if it's a prime number but the only message I get is Key Error.

Hope my message is cleared,

Bests,

Answer 1

your example works

from sympy import isprime
primes = {1: 2, 2: 3, 4: 7, 7:17, 9:37}

print(primes[4]) # 7
print(primes[primes[1]]) # 3
print(primes[primes[4]]) # 17

for k, v in primes.items():
if isprime(v):
print(k, v)

Answer 2

primes[1]=2 ----------1
primes[2]=3-----------3
primes[3]=4

Now , primes[primes[1]]-------2
from 1 , you substitute the value of primes[1] into 2
you get primes[2] which is 3

Answer 3

Ohhhhh right....

print(primes[primes[4]]) is the same saying:
primes[4] = 7
therefore it gives print(primes[7]) # 17

Now I get it Thanks!
@Rohit Thanks for that example, gonna keep it for later. I'm not there yet! ^^'