73 lines
1.8 KiB
Go
73 lines
1.8 KiB
Go
// For more tutorials: https://blog.learngoprogramming.com
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//
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// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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package main
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import (
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"fmt"
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"unicode/utf8"
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"unsafe"
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)
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func main() {
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str := "Yūgen ☯ 💀"
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// can't change a string
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// a string is a read-only byte-slice
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// str[0] = 'N'
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// str[1] = 'o'
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bytes := []byte(str)
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// can change a byte slice
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// bytes[0] = 'N'
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// bytes[1] = 'o'
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str = string(bytes)
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fmt.Printf("%s\n", str)
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fmt.Printf("\t%d bytes\n", len(str))
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fmt.Printf("\t%d runes\n", utf8.RuneCountInString(str))
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fmt.Printf("% x\n", bytes)
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fmt.Printf("\t%d bytes\n", len(bytes))
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fmt.Printf("\t%d runes\n", utf8.RuneCount(bytes))
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// fmt.Println()
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// for i, r := range str {
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// fmt.Printf("str[%2d] = % -12x = %q\n", i, string(r), r)
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// }
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fmt.Println()
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fmt.Printf("1st byte : %c\n", str[0]) // ok
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fmt.Printf("2nd byte : %c\n", str[1]) // not ok
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fmt.Printf("2nd rune : %s\n", str[1:3]) // ok
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fmt.Printf("last rune : %s\n", str[len(str)-4:]) // ok
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// disadvantage: each one is 4 bytes
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runes := []rune(str)
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fmt.Println()
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fmt.Printf("%s\n", str)
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fmt.Printf("\t%d bytes\n", int(unsafe.Sizeof(runes[0]))*len(runes))
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fmt.Printf("\t%d runes\n", len(runes))
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fmt.Printf("1st rune : %c\n", runes[0])
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fmt.Printf("2nd rune : %c\n", runes[1])
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fmt.Printf("first five : %c\n", runes[:5])
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fmt.Println()
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word := "öykü"
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fmt.Printf("%q in runes: %c\n", word, []rune(word))
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fmt.Printf("%q in bytes: % [1]x\n", word)
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fmt.Printf("%s %s\n", word[:2], []byte{word[0], word[1]}) // ö
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fmt.Printf("%c\n", word[2]) // y
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fmt.Printf("%c\n", word[3]) // k
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fmt.Printf("%s %s\n", word[4:], []byte{word[4], word[5]}) // ü
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}
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