How do I understand "and" in a loop

[leoahum]

Hi,

I'm trying to get a better understanding for "and" in a loop. For the script below, I'm trying to get index 1, but it returns index 1 and 2.

b = ["abc", "bcd","cde"]

for i in range(len(b)):
    if "b" and "d" in b[i]:
        print (i)

if I change it like this, and expected no returns (cause none item in b has "bc" and "cd" at the same time), it actually gives me index 1 and 2 again.

b = ["abc", "bcd","cde"]

for i in range(len(b)):
    if "bc" and "cd" in b[i]:
        print (i)

Can someone help? Thanks!