🎉 chapter1 #572
🎉 chapter1 #572
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| @@ -568,7 +574,8 @@ True | |||
| >>> isVowel 'x' | |||
| False | |||
| -} | |||
| isVowel c = error "isVowel: not implemented!" | |||
| isVowel :: Char -> Bool | |||
| isVowel = (`elem` "aoeiuv") | |||
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Nice one! 👍🏼
One note in here, that sometimes, elem could be slower than the explicit pattern matching. I remember there were some benchmarks on one particular case, that showed how moving to pattern matching on each case separately drastically decrease time 🐎 But for this solution it is totally fine!
| last = ax `mod` 10 | ||
| secondlast = ax `mod` 100 `div` 10 |
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That is a wonderful solution! 👏🏼 You correctly noticed that it is the div and mod, cool 😎
Another approach could be also using this: you can see that you use both:
mod m 10
div m 10The standard library has the divMod function, that actually combines inside both div and mod. And this is exactly what you use!.
So you could write it this way:
(x, y) = divMod m 10You can see how we could pattern match on the pair 🙂
src/Chapter1.hs
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| firstDigit :: Int -> Int | ||
| firstDigit x | ||
| | x `div` 10 == 0 = x | ||
| | otherwise = firstDigit (x `div` 10) |
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I see, that for a negative numbers it will be not return the correct answer. Sometimes it is tricky to keep in mind all the edge cases, so no worries, but the idea and recursive solution is awesome 👏🏼
| @@ -490,7 +491,8 @@ Implement a function that returns the last digit of a given number. | |||
| whether it works for you! | |||
| -} | |||
| -- DON'T FORGET TO SPECIFY THE TYPE IN HERE | |||
| lastDigit n = error "lastDigit: Not implemented!" | |||
| lastDigit :: Int -> Int | |||
| lastDigit = (`mod` 10) . abs | |||
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That's pretty!
Nice work on using infix form of calling functions! We don't explain this syntax in our course to make it short. But well done 👍
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Thank you for such a careful and meticulous reply!😀 I have corrected the relevant sections |
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No worries! It is a very great job! Feel free to get to the next Chapter ❤️ |
Solutions for Chapter 1
cc @vrom911