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Why character or string array cannot be constructed like numerical array?

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For eample:
a=[]; a(1:3)=1
but you cannot make string of character the same way:
a=[]; a(1:3)="er"
it returns:
a =
NaN NaN NaN
or
a=[]; a(1:3)='er'
returns this error:
Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
Any idea to make string or character array?

Accepted Answer

Steven Lord
Steven Lord on 2 Apr 2020
You have to start with the correct type of array.
a = "";
a(1:3) = "er"

  2 Comments

Stephen Cobeldick
Stephen Cobeldick on 2 Apr 2020
This is not really equivalent, because
a = "";
actually defines a scalar string array (i.e. one element string (with no characters)), whereas
a = [];
defines an empty double (not a scalar double). To allocate an empty string array use:
a = string([]);
(the MATLAB documentation is very inconsistently written on this topic, sometimes describing "" as an "empty string" (which it isn't, it is scalar), whereas in other places one element strings are clearly described as scalar and also correctly and clearly states that "" defines a "scalar string". So apparently TMW have just proven that 0==1. I shudder to think of the justification that was invented for calling a 1x1 string "empty"...)
James Tursa
James Tursa on 2 Apr 2020
And apparently a third category of this is <missing>. E.g.,
>> clear a
>> a(2) = "er"
a =
1×2 string array
<missing> "er"

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