And operator

Question

I solve a sololearn task called Password Validation
Task: Write a program that takes in a string as input and evaluates it as a valid password. The password is valid if it has at a minimum 2 numbers, 2 of the following special characters ('!', '@', '#', '

Answer 1

Аэн Элле ,
Run below code and read the comments you will get idea.

cnums = 2
csch = 4

print(cnums>=2 and csch>=2)

#below line is executes 2 & csch which 0 so output is False
print(cnums>=2 & csch>=2)

#if you put bracket as below then first conditions evaluate and & operation performed
print((cnums>=2) & (csch>=2))

cnums = 2
csch = 6

print(cnums>=2 and csch>=2)

# csch & 2 is not 0 so output is True
print(cnums>=2 & csch>=2)
print((cnums>=2) & (csch>=2))

cnums = 6
csch = 8

print(cnums>=2 and csch>=2)

# 2 and csch is 0 so output is True
print(cnums>=2 & csch>=2)
print((cnums>=2) & (csch>=2))

Answer 2

suppose cnums is 5 and csch is 2 in that case & will result in 0

Answer 3

Аэн Элле ,
Basically in python bitwise operator has most priority then comparision operator.

So when you write,

C > 2 & B < 4

It will evaluate 2 & B first.

Brackets has most priority so after adding bracket it first evaluate condition and then &.

https://www.mathcs.emory.edu/~valerie/courses/fall10/155/resources/op_precedence.html

Answer 4

helpful table, seems to me i get why they have such priority

thanks for your help :)

Answer 5

thanks, but i still don't understand why in

cnums = 4
csch = 2
print cnums>=2 & csch>=2

without parentheses operator & compares cnums and csch but not the result of comparison (cnums>=2 -- True, csch>=2 -- True)

Answer 6

Аэн Элле You are welcome.