MATLAB: Replace odd numbers with infinity

findodd numbersrandom

I have a code that looks like the following: 
C = randi([100,200],1000,1000);
evenIndices = rem(C,2) == 0
allTheEvenNumbers = C(evenIndices)
allTheEvenNumbers = allTheEvenNumbers -1
locations = find(allTheEvenNumbers)
C(locations) = Inf
I am wanting the odd numbers to be replaced by Inf but it is not working. Where am I going wrong?

Best Answer

%%

C = randi([100,200],3,6)
is_odd = rem(C,2) == 1;
D = C;
D( is_odd ) = inf
returns
C =
   117   103   107   159   122   113
   137   199   184   123   152   191
   134   152   158   145   188   133
D =
   Inf   Inf   Inf   Inf   122   Inf
   Inf   Inf   184   Inf   152   Inf
   134   152   158   Inf   188   Inf
which looks ok.
"Where am I going wrong?"
  • The title says "Replace odd ..." and the code focuses on even
  • experimenting with a large matrix, which is difficult to inspect
  • evenIndices is a logical index, in which true indicates locations with even values. evenIndices is not an optimal name.
  • allTheEvenNumbers is a vector of integers in the range of [ 100, 200 ]. The number of elements in allTheEvenNumbers is approximately half of that in C.
  • it is not meaningsful to substract one from allTheEvenNumbers. Ok, is your intention a negation of a logical value?
  • ...
In response to a comment
In the previous question, there is a requirement to use the function, find()
One may do that, but there is little point
%%
C = randi([100,200],3,6)
C( find( rem(C,2) == 1 ) ) = inf
returns
C =
   180   103   168   139   171   104
   196   185   176   166   103   109
   166   194   175   117   127   183
C =
   180   Inf   168   Inf   Inf   104
   196   Inf   176   166   Inf   Inf
   166   194   Inf   Inf   Inf   Inf
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