Appending to slices in Go - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a slice in Go?

A slice is a flexible and dynamic view into the elements of an array. It can grow and shrink, unlike arrays which have fixed size.

beginner

How do you append an element to a slice in Go?

Use the built-in append() function. For example: slice = append(slice, element) adds element to the end of slice.

intermediate

What happens if the underlying array of a slice is too small when appending?

Go automatically creates a new, larger array, copies the existing elements, and appends the new element. The slice then points to this new array.

intermediate

Can you append multiple elements to a slice at once? How?

Yes. Use append(slice, elem1, elem2, ...) to add multiple elements. Or append another slice using append(slice, otherSlice...).

beginner

Why must you assign the result of append back to the slice variable?

Because append may return a new slice with a different underlying array, you must assign it back to keep the updated slice reference.

What does the append function return in Go?

A The original slice unchanged

B A new slice with the added elements

C An error if the slice is full

D The underlying array

append returns a new slice that includes the original elements plus the new ones.

How do you append all elements of one slice to another?

A append(slice1, slice2...)

B copy(slice1, slice2)

C slice1 + slice2

D append(slice1, slice2)

Use the ... operator to unpack slice2 elements when appending: append(slice1, slice2...).

If you append to a slice without assigning the result, what happens?

A The program crashes

B The slice is updated correctly

C The original slice remains unchanged

D The slice is cleared

append returns a new slice; if you don't assign it, the original slice stays the same.

What is the type of the second argument in append(slice, ...)?

A Only a single element

B Only an array

C Only a slice

D A single element or multiple elements

You can append one or more elements, or use ... to append all elements from another slice.

What happens internally when a slice's capacity is exceeded during append?

A A new larger array is allocated and elements copied

B An error is thrown

C The slice discards old elements

D The slice shrinks

Go allocates a new array with more capacity and copies existing elements when needed.

Explain how the append function works with slices in Go.

Think about what happens when the slice is full and how you keep the updated slice.

Describe how to append multiple elements or another slice to a slice in Go.

Remember the special syntax for unpacking slices.