[R] How to extract integer in a data frame

[Marc Schwartz]

On Apr 21, 2009, at 7:52 PM, Gundala Viswanath wrote:

> Dear all,
>
> I have a data frame that looks like this:
>
>> dat
>
>              V1      V2      V3
> 1          0.000       2 554889
> 2          2.001       0    9978
> 3          0.342       3    5263
> 4          123.000      0    3209
> 5          0.004       0    2434
>
>
> I want to get a subset of that data frame where
> the entry in V1 has (x.000) as its decimal.
>
> yielding
>
>> wanted_dat
>              V1      V2      V3
> 1          0.000       2 554889
> 2          123.000   0    3209
>
> What's the way to do it in R?

At least two possibilities:

# See if the truncated value == value
# See ?trunc
 > subset(dat, trunc(V1) == V1)
    V1 V2     V3
1   0  2 554889
4 123  0   3209


# See if V1 mod 1 == 0
 > subset(dat, V1 %% 1 == 0)
    V1 V2     V3
1   0  2 554889
4 123  0   3209


See ?subset as well.

HTH,

Marc Schwartz