[R] if else does not return right value

[Muhammad Rahiz]

Hi all,

I'm not getting the right results for values that are >99 using the if 
else function. The following illustrates the problem

 > x <- as.matrix(read.table("test.txt"))
 > x
       V1 V2 V3
 [1,]  47  1 43
 [2,]  83  2 42
 [3,]   1  3 41
 [4,]  39  4 40
 [5,]  23  5 39
 [6,]  23  6 38
 [7,]  39  7 37
 [8,]  32  8 36
 [9,]  73  9 35
[10,] 124 10 34

Specifying the followng condition,

if ( x <20){
y <- x +100
} else {
y <- x -100
}

 > y
      V1  V2  V3
 [1,] -53 -99 -57
 [2,] -17 -98 -58
 [3,] -99 -97 -59
 [4,] -61 -96 -60
 [5,] -77 -95 -61
 [6,] -77 -94 -62
 [7,] -61 -93 -63
 [8,] -68 -92 -64
 [9,] -27 -91 -65
[10,]  24 -90 -66

The output generated contains 'errors.

For example, given that x < 20,
for x = 1, the output should be x+100 = 1 + 100 = 101.
However, the generated output is -99.

In addition, there is the following warning message which I don't know 
what it means
    the condition has length > 1 and only the first element will be used

The problem is solved if I use the ifelse function but I want to specify 
the code as following;

if (/condition/) {
/statement 1a
statement 1b
/} else {
/statement 2a
statement 2b
/}

Thanks.

Muhammad

-- 
Muhammad Rahiz  |  Doctoral Student in Regional Climate Modeling					
Climate Research Laboratory, School of Geography & the Environment	
Oxford University Centre for the Environment
South Parks Road, Oxford, OX1 3QY, United Kingdom 
Tel: +44 (0)1865-285194	 Mobile: +44 (0)7854-625974
Email: muhammad.rahiz at ouce.ox.ac.uk