Go Language Learning Notes (1)-arrays and slices

Data (array) and slices (slice)

Array declaration:

ArrayType??? = "[" Arraylength "]" ElementType.

For example:

var a [+] int

var b [3][5] int

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In Go and C, there are several important differences in how arrays work. In Go,

(1) An array is a value type. Assigning an array to another will copy all the elements.

(2)? If you pass an array to the function, it will receive a copy of the array instead of its pointer.

(3) The size of the array is part of its type, and the type [10]int and [20]int are different. After the array length is declared, it cannot be changed.

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Slice declaration:

Slicetype = "["] "ElementType".

For example:

var a []int

The slice without initialization is nil.

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Slices (slice) are encapsulated in arrays, in effect, a slice can be seen as an array of dynamically changing sizes, similar to std::vector in C + +. Just as std::vector is used extensively in actual C + + programming, most of the array programming in GO is done through slices, not simple arrays.

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In general, there are two ways to initialize a slice:

(1) by array

var MyArray [10]int = [10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

var myslice []int = Myarray[:5]

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(2) by Make

Grammar:

Make ([]t, length, capacity)

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Create an initial length of 5 with a capacity of 10 as a slice, and each element of the slice is 0:

Slice1: = Make ([]int, 5, 10)

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Create a slice of length 5 and initialize each element of the slice:

Slice2: = []int{1, 2, 3, 4, 5}

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For slices, the most important feature is that the length is variable:

Slice2: = []int{1, 2, 3, 4, 5}

Fmt. Println ("Slice:", slice2)

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Slice2 = Append (Slice2, 6)

Fmt. Println ("Slice:", slice2)

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Output:

Slice: [1 2 3 4 5]

Slice: [1 2 3 4 5 6]

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Function append is a built-in function that go provides for adding elements to a slice.

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The slice holds a reference to the underlying array, and if you assign one slice to another, both will reference the same array. If a function takes a slice as an argument, the changes it makes to the elements of the slice are visible to the caller, like a pointer to the underlying array.

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Func (f *file) Read (b []byte) (n int, err error)

This OS. File's Read method, which takes a slice parameter, and the length of the slice already sets the upper limit of the data to read. A pointer to a buffer, and the size of the buffer, are required for C/C + +:

int read (file* F, char* buf, int len)

As you can see from here, go is easier to read.

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Source: http://www.cnblogs.com/hustcat/?
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Go Language learning Note (1)-arrays and slices