string 如何在 Erlang 中将整数转换为字符串？

How to convert an integer to a string in Erlang?

提问by collapsinghrung

I know strings in Erlang can be costly to use. So how do I convert "5"to 5?

我知道 Erlang 中的字符串使用起来很昂贵。那么我如何转换"5"为5？

Is there anything like io:format("~p",[5])that would return a formatted string instead of printing to a stream?

有没有类似的东西io:format("~p",[5])会返回格式化的字符串而不是打印到流？

采纳答案by Luke Woodward

The following is probably not the neatest way, but it works:

以下可能不是最简洁的方法，但它有效：

1> lists:flatten(io_lib:format("~p", [35365])).
"35365"

EDIT: I've found that the following function comes in useful:

编辑：我发现以下功能很有用：

%% string_format/2
%% Like io:format except it returns the evaluated string rather than write
%% it to standard output.
%% Parameters:
%%   1. format string similar to that used by io:format.
%%   2. list of values to supply to format string.
%% Returns:
%%   Formatted string.
string_format(Pattern, Values) ->
    lists:flatten(io_lib:format(Pattern, Values)).

EDIT 2(in response to comments): the above function came from a small program I wrote a while back to learn Erlang. I was looking for a string-formatting function and found the behaviour of io_lib:format/2within erlcounter-intuitive, for example:

编辑 2（回应评论）：上述函数来自我前一段时间为学习 Erlang 编写的一个小程序。我一直在寻找一个字符串格式化功能和发现的行为io_lib:format/2中erl反直觉的，例如：

1> io_lib:format("2 + 2 = ~p", [2+2]).
[50,32,43,32,50,32,61,32,"4"]

At the time, I was unaware of the 'auto-flattening' behaviour of output devices mentioned by @archaelus and so concluded that the above behaviour wasn't what I wanted.

当时，我不知道@archaelus 提到的输出设备的“自动展平”行为，因此得出结论，上述行为不是我想要的。

This evening, I went back to this program and replaced calls to the string_formatfunction above with io_lib:format. The only problems this caused were a few EUnit tests that failed because they were expecting a flattened string. These were easily fixed.

今天晚上，我回到这个程序并将对上述string_format函数的调用替换为io_lib:format. 这引起的唯一问题是一些 EUnit 测试失败，因为他们期待一个扁平的字符串。这些很容易解决。

I agree with @gleber and @womble that using this function is overkill for converting an integer to a string. If that's all you need, use integer_to_list/1. KISS!

我同意@gleber 和@womble 的观点，即使用此函数将整数转换为字符串是过度的。如果这就是您所需要的，请使用integer_to_list/1. 吻！

回答by womble

There's also integer_to_list/1, which does exactly what you want, without the ugliness.

还有integer_to_list/1，它完全符合你的要求，没有丑陋。

回答by Thomas

A string is a list:

字符串是一个列表：

9> integer_to_list(123).  
"123"

回答by Gordon Guthrie

As an aside if you ever need to deal with the string representation of floats you should look at the workthat Bob Ippolito has done on mochinum.

顺便说一句，如果你需要处理花车的字符串表示你应该看看的工作鲍勃伊波利托已经上完成mochinum。

回答by Michael Neale

lists:concat([Number]). also works.

列表：concat（[数字]）。也有效。