Statistics and Data Analysis for Microarrays Using R and Bioconductor, 2nd Edition

124 Statistics and Data Analysis for Microarrays Using R and Bioconductor

[1] 2

In the snippet above, the “>” character is the R prompt, showing that R

is ready to accept an input from the user, “1+1” is typed by the user and

is followed by the carriage return (“<CR>”) key.

1

For simplicity, the <CR>

character will not be s hown henceforth even though the user is always expected

to press return at the end of a command. Besides the expected result “2”, R

also produces a “[1]”. This is R’s way of telling us that the result is a scalar,

that is a single value. In general, if more output values are shown on the same

line, the number in brackets is the index ...