From a string to function handle of a function handle
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Hi,
Is it possible to transform a string into a function handle calling another function handle?
More specifically, consider the following simple example
func1=@(x)mean(x)
tmp='@(x)func1(x)+3'
we know that defining
func2=str2func(tmp)
does not work.
Is there any way to create a function handle using tmp that will work?
Thanks
采纳的回答
James Tursa
2017-7-19
func2 = eval(tmp);
2 个评论
Walter Roberson
2017-7-19
... risky
James Tursa
2017-7-20
Yep, agreed. If you don't know where that string is coming from and what could be in it or don't trust the source, then eval should probably be avoided.
更多回答（1 个）
Walter Roberson
2017-7-19
tmp='@(x)feval(evalin(''caller'',''func1''),x)+3'
2 个评论
Patrick Mboma
2017-7-19
Walter Roberson
2017-7-19
The basic issue is that str2func() is operating in a context outside your current workspace, so it does not have access to any variables in your workspace. evalin('caller') gives it that access. You would have the same difficulty with a plain variable:
>> A = 5
A =
5
>> tmp = '@(x) x+A'
tmp =
'@(x) x+A'
>> func2 = str2func(tmp)
func2 =
function_handle with value:
@(x)x+A
>> func2(7)
Undefined function or variable 'A'.
Error in @(x)x+A
str2func always does textual substitutions.
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