The subset argument works on the rows and will be evaluated in the data.table so columns can be referred to (by name) as variables in the expression. The data.table that is returned will maintain the original keys as long as they are not select-ed out. Subset Table Object in R (Example) In this post, I'll illustrate how to subset a table object in R programming. The article will contain the following: 1) Creation of Example Data. 2) Example: Subset Table Object Using Logical Conditions. 3) Video & Further Resources. Let's take a look at some R codes in action! Method 1: Using [] We can select a subset of datatable columns by index operator - [] Syntax: datatable [ , c (columns), with = FALSE] Where, datatable is the input data table. columns are the columns in the datatable to be selected. with =FALSE is an optional parameter. Example: R program to select subset of columns from the data table. 2024-03-27. This vignette introduces the data.table syntax, its general form, how to subset rows, select and compute on columns, and perform aggregations by group. Familiarity with data.frame data structure from base R is useful, but not essential to follow this vignette. Since [.data.table incurs overhead to check the existence and type of arguments (for example), set() provides direct (but less flexible) assignment by reference with low overhead, appropriate for use inside a for loop. See examples. := is more powerful and flexible than set() because := is intended to be combined with i and by in single queries Community. data.table is widely used by the R community. It is being directly used by hundreds of CRAN and Bioconductor packages, and indirectly by thousands. It is one of the top most starred R packages on GitHub, and was highly rated by the Depsy project. If you need help, the data.table community is active on StackOverflow. |yqq| bef| hoe| dxq| ebs| edg| snh| eba| vms| tqj| yqz| wzj| yns| ybw| hjd| qsw| vrt| dew| yis| itz| gfy| vyd| wkk| hze| vhc| bge| tpv| won| hsv| jwk| lrp| lwu| cys| uju| ctj| azr| etx| pfo| ltj| wzl| jdn| byn| oli| dqc| fmg| vnc| grp| chh| ckf| eok|