[r] How to combine multiple conditions to subset a data-frame using "OR"?

I have a data.frame in R. I want to try two different conditions on two different columns, but I want these conditions to be inclusive. Therefore, I would like to use "OR" to combine the conditions. I have used the following syntax before with lot of success when I wanted to use the "AND" condition.

my.data.frame <- data[(data$V1 > 2) & (data$V2 < 4), ]

But I don't know how to use an 'OR' in the above.

You are looking for "|." See http://cran.r-project.org/doc/manuals/R-intro.html#Logical-vectors

my.data.frame <- data[(data$V1 > 2) | (data$V2 < 4), ]

Just for the sake of completeness, we can use the operators [ and [[:

set.seed(1)
df <- data.frame(v1 = runif(10), v2 = letters[1:10])

Several options

df[df[1] < 0.5 | df[2] == "g", ] 
df[df[[1]] < 0.5 | df[[2]] == "g", ] 
df[df["v1"] < 0.5 | df["v2"] == "g", ]

df$name is equivalent to df[["name", exact = FALSE]]

Using dplyr:

library(dplyr)
filter(df, v1 < 0.5 | v2 == "g")

Using sqldf:

library(sqldf)
sqldf('SELECT *
      FROM df 
      WHERE v1 < 0.5 OR v2 = "g"')

Output for the above options:

          v1 v2
1 0.26550866  a
2 0.37212390  b
3 0.20168193  e
4 0.94467527  g
5 0.06178627  j