Programming exercises are rarely a fun activity. In most cases we do them to sharpen skills. But how to get the most out of that activity?

Take a simple exercise to check if a word/string consists of uniq characters (dash ‘-’ and space ‘ ’ can repeat though). This is actually one of the tasks from exercism.org Go learning track.

Here is how I would approach it (code snippets omit imports and other Go source code boilerplate for brevity):

Step 1: Make sure you have good test coverage.

Fortunately exercism.org has me covered here, by provided tests for all exercises.

Step 2: Implement a good-enough solution of the problem.

The main goal is to pass unit tests and commit changes. Code should not be ideal, just like one below:

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func f(word string) bool {
	letters := make(map[rune]bool)
	for _, l := range strings.ToLower(word) {
		if l == ' ' || l == '-' {
			continue
		}
		if _, exists := letters[l]; exists {
			return false
		}
		letters[l] = true
	}
	return true
}

Step 3: Refine your solution.

Now it’s time to make it a bit better. We have a working code already, let’s make it a bit better. Let’s do a few adjustments:

• Rename variables to reflect usage
• Rely on default value of non-existing map elements (line 7)

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func f(word string) bool {
	seen := make(map[rune]bool)
	for _, l := range strings.ToLower(word) {
		if l == ' ' || l == '-' {
			continue
		}
		if seen[l] {
			return false
		}
		seen[l] = true
	}
	return true
}

Step 4: Search for an alternative approach.

Try to solve the same problem using another approach. Let’s switch from if/else to switch, just to check how it goes:

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func f(word string) bool {
	seen := make(map[rune]bool)
	for _, l := range strings.ToLower(word) {
		switch {
		case l == ' ' || l == '-':
			continue
		case seen[l]:
			return false
		default:
			seen[l] = true
		}
	}
	return true
}

Step 5: Check what is available via standard library.

Hmm. Not much changed in the previous iteration. Time to check standard library for an inspiration. For example we can use strings.ContainsRune. In any case the most important is to check available tools once some time is spent on the task.

This may not work well for production development, but it’s perfect for my learning experience at least ;)

Thu Jun 1, 2023 / 435 words / Learn Golang Programming