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49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
1 year ago
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// A slice is a window on an underlying array
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// Pointer, Length, Capacity
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// They can be variable in length!
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package main
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import "fmt"
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// file & package level variable
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var myArray = [...]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
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func main() {
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fmt.Println(myArray)
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//slices can overlap. Since they are a pointer to an underlying arrary. They are mutable.
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s1 := myArray[0:6]
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s2 := myArray[5:len(myArray)]
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fmt.Println(s1)
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fmt.Println(s2)
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myArray[5] = 1337
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fmt.Println(myArray)
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fmt.Println(s1)
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fmt.Println(s2)
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// Writing to a slice changes the underlying arrary
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s1[5] = 7331
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fmt.Println(myArray)
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fmt.Println(s1)
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fmt.Println(s2)
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// Initializing a slice creates and underlying arrary
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var s3 []string
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s3 = append(s3, "Hello")
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s3 = append(s3, "Dirp")
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fmt.Println(s3, len(s3), cap(s3))
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// Another way to make an empty slice with a particular starting size
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s4 := make([]int, 100) // third arg is capacity otherwise len = cap in this invocation
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fmt.Println(s4)
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// gotcha
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fmt.Printf("S2 Len: %d Cap: %d\n", len(s2), cap(s2))
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// This increased the cap of the slice which meant a new array was created.
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// Now what was the overlapping element between s1 and s2 point to different arrays.
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// So changing the first element of s2 no longer updates the last elment of s1.
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s2 = append(s2, 100)
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fmt.Printf("S2 Len: %d Cap: %d\n", len(s2), cap(s2))
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s2[0] = 9000
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fmt.Println(s1)
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fmt.Println(s2)
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}
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