IF "OR" multiple conditions

Question

I have a standard 2x2 table

      Yes   No
Yes    a    b
No     c    d

I want to create a condition whereby IF(a or b or c or d = 0) then 0.5 is added on to each of the cells a,b,c,d.

I have tried this:

  if(a && b && c && d == 0){
    a=a+0.5, b=b+0.5, c=c+0.5, d=d+0.5
  }

But I am getting an error saying

Error: unexpected ',' in:
"if(a && b && c && d== 0){
a=a+0.5,"

i.e. I don't think it is letting me put multiple things to execute.

Also I don't think that the && is right between each of the letters as I believe that means IF(a and b and ...)

UPDATE TO QUESTION:

I have another related question.

If I have say a set of say n tables, all in the format:

      Yes   No
Yes    a    b
No     c    d

and if one of the a,b,c or d in any of the n tables is equal to zero then 0.5 is added on to each of the a,b,c,d for all of the n tables. How would I do that?

My list looks like the following:

    n11   n12  n21   n22
1   188  1157  173  1168
2     2   201    1   101
3   369  2280  354  2289
4     1    61    0    61
5  1306 16870 1333 16773
6     4    81    3    79
7     6   117    5   118
8    19   334   15   318
9     1    49    0    48
10    0    36    1    33
11    2   114    3   113
12   13   433   37   696
13    1    64    0    65
14    4   157    1   160
15    1    42    0    43
16    1   150    5   146
17    7  1124   10  1117
18    2    78    2    77

and what I am trying to say is that if any of the aspects of the cells of the table are 0, then I want 0.5 to be added on to every cell.

Answer 1

In R you can't use , to separate line, but you can use ;.

Also, the way you are doing considers a,b and c are boolean (TRUE/FALSE), which is not the case as they are numbers. Your condition should be :

if (a == 0 || b == 0 || c == 0 || d == 0)

Note that your code will run nevertheless, even if a,b and c are not boolean since they are numbers and there is an equivalence between FALSE and a == 0. This means you could also write your condition as :

if (!a || !b || !c || !d)

For the UPDATE, I consider matList is the list of matrices :

for (ii in  1:length(matList())) {
    if (any(matList[[ii]] == 0)) {  
        matList = lapply(matList, function(X){X+0.5})
        break # Exit the for loop
    }
}

lapply applies mat + 0.5 (i.e + 0.5 to each element of the matrix thanks to R sugar) to every element (here matrices) of the list matList and returns the resulting list.

Answer 2

The problem is with the commas that separate your variables. R syntax does not allow you to do it. Write it this way:

if (a && b && c && d == 0){
    a=a+0.5
    b=b+0.5
    c=c+0.5
    d=d+0.5
}

Another problem is that the behaviour you described does not match with your code. If you write && it means and, not or. If you want to check if each element is equal to 0, you should write the following:

Modified based on Rodrigo's comment, the correct code would be:

if (0 %in% c(a,b,c,d)){
    a=a+0.5
    b=b+0.5
    c=c+0.5
    d=d+0.5
}