# Putting NULLs in between the string array.

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MakM on 30 Mar 2022
Commented: MakM on 30 Mar 2022
I have string array A={'a','b','c','d','e'}, and index vector index=[1,3,5]. I want to put NULL values at this location and shift other values. For example my output should be like this: Output={[],'a','b',[],'c','d',[],'e'}. How can I do that.

Simon Chan on 30 Mar 2022
Hope I understand it correctly, try this:
A={'a','b','c','d','e'};
index=[1,3,5];
newindex = index+(0:length(index)-1);
N = length(A)+length(index);
Output = repelem({''},1,N);
Output(~ismember(1:N,newindex))=A
Output = 1×8 cell array
{0×0 char} {'a'} {'b'} {0×0 char} {'c'} {'d'} {0×0 char} {'e'}
Simon Chan on 30 Mar 2022
Edited: Simon Chan on 30 Mar 2022
May I know the definition of the index?
For the previous answer, I assume the empty cell happens before the 1st, 3rd and 5th letters.
Did your definition refers to the location of the empty positions like the following?
A={'a','b','c','d','e'};
index=[1,2,3,5];
N = length(A)+length(index);
Output = repelem({''},1,N);
Output(~ismember(1:N,index))=A
Output = 1×9 cell array
{0×0 char} {0×0 char} {0×0 char} {'a'} {0×0 char} {'b'} {'c'} {'d'} {'e'}
MakM on 30 Mar 2022
Thanks for the answer. Yes this is what I exactly want :)

Mathieu NOE on 30 Mar 2022
hello
here you are
A={'a','b','c','d','e'};
index=[1,3,5];
%% main code
ll = numel(A)+numel(index);
index_comp = (1:ll);
index2 = index + (0:numel(index)-1);
index_comp(index2) = [];
Output = cell(1,ll);
Output(index_comp) = A
MakM on 30 Mar 2022
Hey..
It is not working correct in the case if I want to put NULL on two consective values, for example if the index is [1,2,3,5], then not working correct.