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Challenges

Comments on How many odd digits?

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How many odd digits?

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Given a positive integer, count its odd digits.

Input

  • An integer from 1 to 999,999,999, inclusive, in any of the following formats:
    • A number (such as an integer or floating point number), like 123.
    • A string, like "123".
    • A sequence of characters (such as an array or list), like ['1', '2', '3'].
    • A sequence of single digit numbers, like [1, 2, 3].

Output

  • The number of odd digits in the input.

Test cases

Test cases are in the format input : output.

1 : 1
2 : 0
3 : 1
4 : 0
5 : 1
6 : 0
7 : 1
8 : 0
9 : 1
10 : 1
11 : 2
12 : 1
13 : 2
14 : 1
15 : 2
16 : 1
17 : 2
18 : 1
19 : 2
20 : 0
111111111 : 9
222222222 : 0
123456789 : 5
999999999 : 9

Scoring

This is a code golf challenge. Your score is the number of bytes in your code. Lowest score for each language wins.

Explanations are optional, but I'm more likely to upvote answers that have one.

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Input format (5 comments)
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JavaScript, 25 bytes

Input as an array of digits

a=>a.map(x=>t+=x%2,t=0)|t

Try it online!

26 bytes

With input as a string (or an array of digit strings).

f=([d,...a])=>d?d%2+f(a):0

Try it online!

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Same length and perhaps easier to understand: `a=>a.reduce((s,a)=>s+a%2)` (1 comment)
Same length and perhaps easier to understand: `a=>a.reduce((s,a)=>s+a%2)`
Karl Knechtel‭ wrote about 2 months ago

Same length and perhaps easier to understand: a=>a.reduce((s,a)=>s+a%2)