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doc: split array example & some tweaks (#5564)

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Nick Treleaven 2020-06-30 13:37:02 +01:00 committed by GitHub
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@ -389,10 +389,38 @@ println(s) // "hello\nworld"
mut nums := [1, 2, 3]
println(nums) // "[1, 2, 3]"
println(nums[1]) // "2"
nums[1] = 5
println(nums) // "[1, 5, 3]"
println(nums.len) // "3"
nums = [] // The array is now empty
println(nums.len) // "0"
// Declare an empty array:
users := []int{}
// We can also preallocate a certain amount of elements.
ids := []int{ len: 50, init: 0 } // This creates an array with 50 zeros
```
The type of an array is determined by the first element:
* `[1, 2, 3]` is an array of ints (`[]int`).
* `['a', 'b']` is an array of strings (`[]string`).
If V is unable to infer the type of an array, the user can explicitly specify it for the first element: `[byte(0x0E), 0x1F, 0xBA, 0x0E]`
V arrays are homogeneous (all elements must have the same type). This means that code like `[1, 'a']` will not compile.
`.len` field returns the length of the array. Note that it's a read-only field,
and it can't be modified by the user. Exported fields are read-only by default in V.
See [Access modifiers](#access-modifiers).
```v
mut nums := [1, 2, 3]
nums << 4
println(nums) // "[1, 2, 3, 4]"
// append array
nums << [5, 6, 7]
println(nums) // "[1, 2, 3, 4, 5, 6, 7]"
@ -402,31 +430,14 @@ names << 'Sam'
// names << 10 <-- This will not compile. `names` is an array of strings.
println(names.len) // "3"
println('Alex' in names) // "false"
names = [] // The array is now empty
// Declare an empty array:
users := []User{}
// We can also preallocate a certain amount of elements.
ids := []int{ len: 50, init: 0 } // This creates an array with 50 zeros
```
The type of an array is determined by the first element: `[1, 2, 3]` is an array of ints (`[]int`).
`['a', 'b']` is an array of strings (`[]string`).
If V is unable to infer the type of an array, the user can explicitly specify it for the first element: `[byte(0x0E), 0x1F, 0xBA, 0x0E]`
V arrays are homogeneous (all elements must have the same type). This means that code like `[1, 'a']` will not compile.
`<<` is an operator that appends a value to the end of the array.
It can also append an entire array.
`.len` field returns the length of the array. Note, that it's a read-only field,
and it can't be modified by the user. Exported fields are read-only by default in V.
`val in array` returns true if the array contains `val`. See [`in` operator](#in-operator).
`val in array` returns true if the array contains `val`.
#### Array methods
All arrays can be easily printed with `println(arr)` and converted to a string
with `s := arr.str()`.