Lua string.format 选项

Lua string.format options

提问by RCIX

This may seem like a stupid question, but what are the symbols used for string replacement in string.format? can someone point me to a simple example of how to use it?

这似乎是一个愚蠢的问题，但是 string.format 中用于字符串替换的符号是什么？有人可以指出我如何使用它的简单示例吗？

回答by Robert Harvey

string.format in Lua follows the same patterns as Printf in c:

Lua 中的 string.format 与 c 中的 Printf 遵循相同的模式：

http://www.cplusplus.com/reference/clibrary/cstdio/printf/

http://www.cplusplus.com/reference/clibrary/cstdio/printf/

There are some exceptions, for those see here:

有一些例外，请参见此处：

http://pgl.yoyo.org/luai/i/string.format

http://pgl.yoyo.org/luai/i/string.format

回答by RBerteig

Chapter 20 of PiLdescribes string.formatnear the end:

PiL 的第 20 章string.format在结尾处描述了：

The function string.formatis a powerful tool when formatting strings, typically for output. It returns a formatted version of its variable number of arguments following the description given by its first argument, the so-called format string. The format string has rules similar to those of the printffunction of standard C: It is composed of regular text and directives, which control where and how each argument must be placed in the formatted string.

string.format在格式化字符串时，该函数是一个强大的工具，通常用于输出。它根据第一个参数（即所谓的格式字符串）给出的描述，返回其可变数量参数的格式化版本。格式字符串的规则类似于printf标准 C 函数的规则：它由常规文本和指令组成，它们控制每个参数必须放在格式化字符串中的位置和方式。

The Lua Referencesays:

在Lua中引用说：

The format string follows the same rules as the printffamily of standard C functions. The only differences are that the options/modifiers *, l, L, n, p, and hare not supported and that there is an extra option, q.

格式字符串遵循与printf标准 C 函数系列相同的规则。唯一的区别是选项/修饰符*，l，L，n， p，和h不支持，并且有一个额外的选项，q。

The function is implemented by str_format()in strlib.cwhich itself interprets the format string, but defers to the C library's implementation of sprintf()to actually format each field after determining what type of value is expected (string or number, essentially) to correspond to each field.

该功能是通过执行str_format()在strlib.c其本身解释该格式串，但是推迟到C库的执行sprintf()确定的值类型预期什么（字符串或数字，基本上）以对应于每个字段后到实际上格式化每个字段。

回答by Nick Dandoulakis

There should be "Lua Quick Reference" html file in your hard disk, if you used an installation package.
(for example: ../Lua/5.1/docs/luarefv51.html)

如果您使用安装包，您的硬盘中应该有“Lua 快速参考”html 文件。
（例如：../Lua/5.1/docs/luarefv51.html）

There you'll find, among other things,

在那里你会发现，除其他外，

string.format (s [, args ])

string.format (s [, args ])

• Formatting directives
• Formatting field types
• Formatting flags
• Formatting examples

• 格式化指令
• 格式化字段类型
• 格式化标志
• 格式化示例