Array Literals and Parameters

Array literals

When the values (or some of them) of the items are known beforehand, a simpler initialization exists using the { , ,} notation called array literals (or constructors) instead of initializing every item in the [ ]= way. Let’s see some variants.

1^st variant

Specify explicitly the size n of the array with [n]. For example:

var arrAge = [5]int{18, 20, 15, 22, 16}

Here is another example:

var arr = [10]int{ 1, 2, 3 }

This is an array of 10 elements with the 1^st three different from 0.

2^nd variant

The […] notation, for example:

var arrLazy = [...]int{5, 6, 7, 8, 22}

... indicates the compiler has to count the number of items to obtain the length of the array. However, [...]int is not a type, so this is illegal:

var arrLazy [...]int = [...]int{5, 6, 7, 8, 22}

If the ... is omitted then a slice is created.

3^rd variant

The index: value syntax can be followed. For example:

var arrKeyValue = [5]string{3: "Chris", 4: "Ron"}

Passing an array to a function

Passing big arrays to a function quickly eats up a lot of memory because arrays are copied when passing. There are 2 ways to prevent this:

• Pass a pointer to the array.
• Use a slice of the array (we’ll discuss slices in the next section).

The following example illustrates the first solution: