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Slices in Go

99 times out of 100 you will use a slice instead of an array when working with ordered lists.

Arrays are fixed in size. Once you make an array like [10]int you can't add an 11th element.

A slice is a dynamically-sized, flexible view of the elements of an array.

The zero value of slice is nil.

Non-nil slices always have an underlying array, though it isn't always specified explicitly. To explicitly create a slice on top of an array we can do:

primes := [6]int{2, 3, 5, 7, 11, 13}
mySlice := primes[1:4]
// mySlice = {3, 5, 7}

The syntax is:

arrayname[lowIndex:highIndex]
arrayname[lowIndex:]
arrayname[:highIndex]
arrayname[:]

Where lowIndex is inclusive and highIndex is exclusive.

lowIndex, highIndex, or both can be omitted to use the entire array on that side of the colon.

Sequence Slicing

Adjust the slice controls and watch values move into the result.

stop

start

champions[0:2]

Assignment

Retries are a premium feature now! Textio's free users only get 1 retry message, while pro members get an unlimited amount.

Complete the getMessageWithRetriesForPlan function. It takes a plan variable as input as well as an array of 3 messages. You've been provided with constants representing the plan types at the top of the file.

If the plan is a pro plan, return all the strings from the messages input in a slice.
If the plan is a free plan, return the first 2 strings from the messages input in a slice.
If the plan isn't either of those, return a nil slice and an error that says unsupported plan.