Golang 可以像 Python 那样乘以字符串吗？
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Can Golang multiply strings like Python can?
提问by Duke Dougal
Python can multiply strings like so:
Python 可以像这样将字符串相乘：
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?
Golang 能以某种方式做同样的事情吗？
采纳答案by Mark Reed
It has a function instead of an operator, strings.Repeat. Here's a port of your Python example, which you can run here:
它有一个函数而不是一个运算符，strings.Repeat。这是您的 Python 示例的一个端口，您可以在此处运行：
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:
请注意，我使用了utf8.RuneCountInString(x)而不是len(x); 前者计算“符文”（Unicode 代码点），而后者计算字节。在 的情况下"my new text is this long"，差异无关紧要，因为所有字符都只有一个字节，但是养成指定您的意思的习惯是很好的：
len("ā") //=> 2
utf8.RuneCountInString("ā") //=> 1
(In Python 2, lencounts bytes on plain strings and runes on Unicode strings (u'...'):
（在 Python 2 中，len计算纯字符串上的字节数和 Unicode 字符串上的符文 ( u'...')：
>>> len('ā') #=> 2
>>> len(u'ā') #=> 1
In Python 3, plain strings areUnicode strings and lencounts runes; if you want to count bytes, you have to encode the string into a bytearrayfirst, which you can do with a literal using the b'...'quoting syntax.:
在 Python 3 中，纯字符串是Unicode 字符串，并len计算符文；如果要计算字节数，则必须将字符串编码为bytearray第一个，您可以使用b'...'引用语法对文字进行编码。：
>>> len('ā') #=> 1
>>> len(b'ā') #=> 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.)
在 Go 中，只有一种字符串。所以你不必转换，但你必须选择与你想要的语义匹配的函数。）
回答by icza
Yes, it can, although not with an operator but with a function in the standard library.
是的，它可以，虽然不是使用运算符，而是使用标准库中的函数。
It would be very easy with a simple loop, but the standard library provides you a highly optimized version of it: strings.Repeat().
使用简单的循环会很容易，但标准库为您提供了高度优化的版本：strings.Repeat().
Your example:
你的例子：
x := "my new text is this long"
y := strings.Repeat("#", len(x))
fmt.Println(y)
Try it on the Go Playground.
在Go Playground上试一试。
Notes: len(x)is the "bytes" length (number of bytes) of the string (in UTF-8 encoding, this is how Go stores strings in memory). If you want the number of characters (runes), use utf8.RuneCountInString().
注意：len(x)是字符串的“字节”长度（字节数）（在 UTF-8 编码中，这是 Go 在内存中存储字符串的方式）。如果您想要字符数（符文），请使用utf8.RuneCountInString().
回答by ShadowRanger
Yup. The strings package has a Repeatfunction.
是的。strings 包有一个Repeat函数。
