How to subset a data.table object using a range of values in R?

To subset a data.table object using a range of values, we can use single square brackets and choose the range using %between%. For example, if we have a data.table object DT that contains a column x and the values in x ranges from 1 to 10 then we can subset DT for values between 3 to 8 by using the command DT[DT$x %between% c(3,8)].

Example1

Loading data.table package and creating a data.table object −

library(data.table)
x1<-rnorm(20)
x2<-rnorm(20,100,3.25)
dt1<-data.table(x1,x2)
dt1

Output

       x1         x2
1:   0.06546822   102.83348
2:   1.05756760   99.28015
3:   0.09397791   97.36582
4:  -0.44478256   96.22510
5:  -0.17392089   99.56077
6:   0.32834773   95.85831
7:  -0.04563975   104.88298
8:   0.95807930   95.31325
9:   1.25349243   101.72948
10:  0.47676550   96.76459
11: -1.26790256   98.76222
12: -1.36220203   97.91117
13: -1.31999499   102.81730
14:  1.69391374   96.00380
15: -0.10801512   101.69544
16: -1.13463486   108.11833
17: -0.13885823   102.34798
18: -0.54403332   99.68874
19:  0.55865944   97.33505
20:  0.76511431   96.53975

Subsetting rows of dt1 for values 0.5 to 1 of x1 −

dt1[dt1$x1 %between% c(0.5,1)]

      x1         x2
1: 0.9580793  95.31325
2: 0.5586594  97.33505
3: 0.7651143  96.53975

Example2

y1<-rpois(20,5)
y2<-rpois(20,2)
dt2<-data.table(y1,y2)
dt2

Output

    y1 y2
1:  7  1
2:  3  2
3:  1  5
4:  4  2
5:  5  3
6:  4  1
7:  3  2
8:  5  0
9:  5  2
10: 7  4
11: 5  4
12: 6  2
13: 6  4
14: 6  2
15: 5  2
16: 1  1
17: 3  1
18: 2  4
19: 4  0
20: 4  1

Subsetting rows of dt1 for values 2 to 6 of y2 −

dt2[dt2$y2 %between% c(2,6)]

    y1 y2
1:  3  2
2:  1  5
3:  4  2
4:  5  3
5:  3  2
6:  5  2
7:  7  4
8:  5  4
9:  6  2
10: 6  4
11: 6  2
12: 5  2
13: 2  4

Nizamuddin Siddiqui

Updated on: 06-Mar-2021

2K+ Views

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