Lua中将计算字符串转换为int [英] Converting calculation string to int in Lua

问题描述

我正在尝试将具有多个数字的字符串转换为单个 int像这样:

I'm trying to get a string with multiple numbers to a single int like this:

x="5+5"  --amount of numbers is not constant
y=tonumber(x)
print(y) 

结果是 nil 而它应该是 10 (int).我可以解决这个问题的唯一方法是首先使用 string.find() 搜索所有 "+" 和 "-" 然后将其剪切到所有必要的部分，然后只是 tonumber().为这样一个简单的问题编写至少一百行代码感觉很愚蠢.

The result of this is nil while it should be 10 (int). The only way I could solve this is by first searching all the "+" and "-" with string.find() then cutting it to all the necessary parts and from there just tonumber(). It feels stupid to code at least a hundred rows of code for such a simple problem.

推荐答案

tonumber 只能用于实数字符串，不能用于算术表达式.

tonumber can be used only on a string that is a real number, not an arithmetic expression.

您可以加载字符串并运行它:

You can load the string and run it:

x = "5 + 5"
func = assert(load("return " .. x))
y = func()
print(y)

在 Lua 5.1 中，使用 loadstring 而不是 load.

In Lua 5.1, use loadstring instead of load.

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