Please can anyone tell me why the output is like this ? (Python)

Question

I am beginner programmer in python and i dont know why the input of this code isnt as i expect it to be:

def count_smileys(arr):
    #the number of valid smiley faces in array/list
    smileys_count = 0
    for character in arr:
        if len(character) == 2:
            if character[0] == ":" or character[0] == ";" and character[2] == ")" or character[2] == "D":
                smileys_count += 1
        if len(character) == 3:
            if character[0] == ":" or character[0] == ";" and character[2] == ")" or character[2] == "D" and character[2] == "-" or character[2] == "~":
                smileys_count +=1

    return(smileys_count)

and the output is this :

my output

Remember that the second character in a string has an index of 1, not 2. — Andy, Oct 04 '19 at 18:58
if `len(character) == 2` then `character[2]` will result in an exception — rdas, Oct 04 '19 at 18:59
Welcome to SO. You should paste your code in the question, not link to a png snapshot. — Demi-Lune, Oct 04 '19 at 20:03
Thank you .Yes I tried to but I wanted you to know what is the challange assigment — Doomes, Oct 04 '19 at 20:13

score 1 · Answer 1 · answered Oct 04 '19 at 19:01

You missed parenthesis, when you mix in a sentence AND/OR, you usually need parenthesis:

def count_smileys(arr):
    #the number of valid smiley faces in array/list
    smileys_count = 0
    for character in arr:
        if len(character) == 2:
            if (character[0] == ":" or character[0] == ";") and (character[1] == ")" or character[1] == "D"):
                smileys_count += 1
        if len(character) == 3:
            if (character[0] == ":" or character[0] == ";") and (character[1] == ")" or character[1] == "D") and (character[2] == "-" or character[2] == "~"):
                smileys_count +=1

    return(smileys_count)

Also, your indexes are wrong

No they are not wrong i just wrote them in weird order because the character - and ~ are in the middle of the string if strings len is 3 — Doomes, Oct 04 '19 at 19:44

Igor F. · Accepted Answer · 2019-10-06T06:27:42.843

1

It's the logical operator precedence problem: and has a higher priority than or, much like * has a precedence over +. You should use parentheses.

if len(character) == 2:
  if (character[0] == ":" or character[0] == ";") and (character[1] == ")" or character[1] == "D"):
    smileys_count += 1

etc.

See also Priority of the logical statements NOT AND & OR in python.

edited Oct 06 '19 at 06:27

answered Oct 04 '19 at 19:04

Igor F.

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but the `len(character)==2` meaning the indices are just `0 and 1` so how will `character[2]` work? – Onyambu Oct 04 '19 at 19:48
but it says that the len is 3 in that instance – Doomes Oct 04 '19 at 19:51

Please can anyone tell me why the output is like this ? (Python)

2 Answers2