doudou1855
2015-10-15 02:52
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Golang可以像Python一样乘以字符串吗?

Python can multiply strings like so:

Python 3.4.3 (default, Mar 26 2015, 22:03:40)
[GCC 4.9.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> x = 'my new text is this long'
>>> y = '#' * len(x)
>>> y
'########################'
>>>

Can Golang do the equivalent somehow?

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3条回答 默认 最新

  • dongmeng0317 2015-10-15 02:54
    已采纳

    It has a function instead of an operator, strings.Repeat. Here's a port of your Python example, which you can run here:

    package main
    
    import (
        "fmt"
        "strings"
        "unicode/utf8"
    )
    
    func main() {
        x := "my new text is this long"
        y := strings.Repeat("#", utf8.RuneCountInString(x))
        fmt.Println(x)
        fmt.Println(y)
    }
    

    Note that I've used utf8.RuneCountInString(x) instead of len(x); the former counts "runes" (Unicode code points), while the latter counts bytes. In the case of "my new text is this long", the difference doesn't matter since all the characters are only one byte, but it's good to get into the habit of specifying what you mean:

    len("ā") //=> 2
    utf8.RuneCountInString("ā") //=> 1
    

    (In Python 2, len counts bytes on plain strings and runes on Unicode strings (u'...'):

    >>> len('ā') #=> 2
    >>> len(u'ā') #=> 1
    

    In Python 3, plain strings are Unicode strings and len counts runes; if you want to count bytes, you have to encode the string into a bytearray first:

    >>> len('ā') #=> 1
    >>> len('ā'.encode('utf-8')) #=> 2
    

    In Go, there's only one kind of string. So you don't have to convert, but you do have to pick the function that matches the semantics you want.)

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