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https://github.com/golang/go
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289a357104
Originally published on The Go Programming Language Blog, January 25, 2011. http://blog.golang.org/2011/01/json-and-go.html R=adg CC=golang-dev https://golang.org/cl/5846044
43 lines
696 B
Go
43 lines
696 B
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"fmt"
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"math"
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)
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func InterfaceExample() {
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var i interface{}
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i = "a string"
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i = 2011
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i = 2.777
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// STOP OMIT
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r := i.(float64)
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fmt.Println("the circle's area", math.Pi*r*r)
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// STOP OMIT
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switch v := i.(type) {
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case int:
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fmt.Println("twice i is", v*2)
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case float64:
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fmt.Println("the reciprocal of i is", 1/v)
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case string:
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h := len(v) / 2
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fmt.Println("i swapped by halves is", v[h:]+v[:h])
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default:
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// i isn't one of the types above
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}
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// STOP OMIT
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}
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func main() {
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InterfaceExample()
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}
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