I have an R matrix named ddd. When I enter this, everything works fine:

i <- 1
shapiro.test(ddd[,y])
ad.test(ddd[,y]) 
stem(ddd[,y]) 
print(y) 

The calls to Shapiro Wilk, Anderson Darling, and stem all work, and extract the same column.

If I put this code in a "for" loop, the calls to Shapiro Wilk, and Anderson Darling stop working, while the the stem & leaf call and the print call continue to work.

for (y in 7:10) {
    shapiro.test(ddd[,y])
    ad.test(ddd[,y]) 
    stem(ddd[,y]) 
    print(y)
}

The decimal point is 1 digit(s) to the right of the |

  0 | 0
  0 | 899999
  1 | 0

[1] 7

The same thing happens if I try and write a function. SW & AD do not work. The other calls do.

> D <- function (y) {
+ shapiro.test(ddd[,y])
+ ad.test(ddd[,y]) 
+ stem(ddd[,y]) 
+ print(y)  }

> D(9)

  The decimal point is at the |

   9 | 000
   9 | 
  10 | 00000

[1] 9

Why don't all the calls behave the same way?