Conditionally replace numerical Array with Strings

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Metin Akyol 2021-11-22

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评论： Metin Akyol 2021-11-22

I have a simply array with 0s and 1s and I would like to replace each element conditionally with a string like so:

old_array = [0 1 0 0 1]

new_array = ["string0" "string1" "string0" "string0" "string1"]

I have tried this, but ended up with NaNs:

old_array(old_array>0)=string("string1")

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Answer 1

Dave B 2021-11-22

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This is happening because old_array is an array of doubles, you can't have a mix of strings and doubles in a regular (i.e. not cell) array.

You can convert an array to string and replace all of the values

old_array = [0 1 0 0 1];
old_array = "string" + string(old_array)
old_array = 1×5 string array
    "string0"    "string1"    "string0"    "string0"    "string1"

Or convert the array to string and just replace some of the values (and still keep everything string):

old_array = [0 1 0 0 1];
ind = old_array>0;
old_array = string(old_array);
old_array(ind) = "string1"
old_array = 1×5 string array
    "0"    "string1"    "0"    "0"    "string1"

Or you can use a cell array to mix and match types:

old_array = [0 1 0 0 1];
ind = old_array>0;
old_array = num2cell(old_array);
old_array(ind)={"string1"}
old_array = 1×5 cell array
    {[0]}    {["string1"]}    {[0]}    {[0]}    {["string1"]}