Can you extract an element from an array in the same line as you create the array?

Question

Jack Warren 2019-5-16

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编辑： Guillaume 2019-5-17

Hi,

I am wondering if it possible to extract data from an array in the same line as the array is created. The purpose is to remove the need for a separate line of code in which the data is extracted.

Example of separate array creation and data extraction:

s = "hello world";
t = split(s, " "); % In this line the array "t" is created
t(1) % In this line the first element of "t" is extracted
>> ans = 
    "hello"

My question: Can lines 2 and 3 be combined? Something like this:

t = split(s, " ")(1)
>> ans = 
    "hello"

Thanks in advance,

Jack

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Answer 1

Guillaume 2019-5-16

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No, unfortunately in matlab, you cannot index directly into the return value of a function.

You could use subsref as demonstrated by Madhan to do the indexing, however I would advise against that.Yes, subsref is the function actually called when you perfom indexing but the lack of clarity and the high chance of making a mistake don't make it worth it just so you can write one line of code instead of two.

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Jack Warren 2019-5-17

Thanks for the explanation Guillaume. I will trial subsref with caution.

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Answer 2

madhan ravi 2019-5-16

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在 MATLAB Online 中打开

Why not?

regexp(s,'\w*','match','once')

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Jack Warren 2019-5-17

编辑：Jack Warren 2019-5-17

Thanks for the answers. As Guillaume has suggested substrct may not work reliably, so I will trial it with caution.

Guillaume 2019-5-17

编辑：Guillaume 2019-5-17

subsref will always work (as long as you've constructed the arguments properly). My point was that using it for the sake of saving one line is not a good idea as it makes the code more obscure. I would always favour clarity over conciseness. It is often said that code is Write Once Read Many, so you should concentrate on making the code easier to read even if it takes longer to write.

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