# A compact way to find single digit numbers (i.e. numbers between 0 and 9) and replace them with two digit numbers

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Sim on 9 Aug 2022
Commented: Sim on 11 Aug 2022
A compact way to find single digit numbers (i.e. numbers between 0 and 9) and replace them with two digit numbers ?
For example, from:
a = [ 8
12
15
76
3
99
0];
I would like to add a zero in front of the single digit numbers:
b = [08
12
15
76
03
99
00];
Sim on 11 Aug 2022
I did not think to cause such a fuss :-) ....but the conversation is very interesting, thanks!

John D'Errico on 9 Aug 2022
Edited: John D'Errico on 9 Aug 2022
In MATLAB, you CANNOT store a number in a numeric format as one that has a leading zero.
If you want to convert the numbers to character form, then it is trivial. One line is sufficient.
a = [ 8
12
15
76
3
99
0];
d = dec2base(a,10)
d = 7×2 char array
'08' '12' '15' '76' '03' '99' '00'
The result is no longer usable as a number though. It is effectively only a picture of a number at that point, or perhaps I should say a caricature, if you can stand the pun.
Sim on 9 Aug 2022
Thanks a lot! I would like to accept both of your answers!!!

dpb on 9 Aug 2022
For what purpose and in what context? You will only be able to show the leading zeros if you convert the numeric values to some form of text in which case it's trivial
>> compose('%02d',a)
ans =
7×1 cell array
{'08'}
{'12'}
{'15'}
{'76'}
{'03'}
{'99'}
{'00'}
>>
Well, there is one other way --
>> categorical(ans)
ans =
7×1 categorical array
08
12
15
76
03
99
00
>>
but if you want a straight, ordinary double array to appear that way at the command line, just not possible.
Sim on 9 Aug 2022
Thanks a lot! I would like to accept both of your answers!!!