eval函数全名

eval()是程序语言中的函数，功能是获取返回值，不同语言大同小异，函数原型是返回值 = eval( codeString )，如果eval函数在执行时遇到错误，则抛出异常给调用者。

JavaScript

函数功能

eval() 函数可将字符串转换为代码执行，并返回一个或多个值

函数原型

返回值 = eval( codeString )

函数说明

如果eval函数在执行时遇到错误,则抛出异常给调用者.

类似的函数是loadcode ,loadcode并不立即执行代码,而是返回一个函数对象.

并且loadcode支持路径参数,eval并不支持. eval并不支持代码中的return语句,而是将代码作为表达式直接计算出结果.

实例

var d = eval("({name:"chentong"})")

alert(d.name);

Matlab

Function

Execute string containing MATLAB expression

Syntax

eval(expression)

[a1, a2, a3, ...] = eval("myfun(b1, b2, b3, ...)")

Description

eval(expression) executes expression, a string containing any valid MATLAB expression. You can construct expression by concatenating substrings and variables inside square brackets:

expression = [string1, int2str(var), string2, ...]

[a1, a2, a3, ...] = eval("myfun(b1, b2, b3, ...)") executes function smyfun with arguments b1, b2, b3, ..., and returns the results in the specified output variables.

Remarks

Using the eval output argument list is recommended over including the output arguments in the expression string. The first syntax below avoids strict checking by the MATLAB parser and can produce untrapped errors and other unexpected behavior. Use the second syntax instead:

% Not recommended

eval("[a1, a2, a3, ...] = function(var)")

% Recommended syntax

[a1, a2, a3, ...] = eval("function(var)")