How to filter by a member in column

Question

I have a column which is like below in my data table:

Category
_________
{A}
{B}
{C}
{A,B}
{A,C}
{C}
{C,A,B}
{A}
{A,C}

from this I want to select where the rows where A is a member of category. I am currently using

DT[Category=="{A}"]

to filter out the rows where category= A but rather than this I would like to have rows which category contains A (like member of in postgres) . Any help is appreciated.

See `?grepl` for pattern matching. Something like: `DT[grepl('A', Category)]` or `DT[grepl('A', Category, fixed = TRUE)]` — Jaap, Jun 22 '17 at 11:05

score 2 · Accepted Answer · answered Jun 22 '17 at 11:13

# Data
df <- read.delim(textConnection('Category
{A}
{B}
{C}
{A,B}
{A,C}
{C}
{C,A,B}
{A}
{A,C}'))


# Slice, keeping only rows in 'Category' containing character 'A'
subset(df, grepl('A', Category))

  Category
1      {A}
4    {A,B}
5    {A,C}
7  {C,A,B}
8      {A}
9    {A,C}

Gangesh Dubey · Answer 2 · 2017-06-23T06:03:39.690

0

grep should come handy here

DT[grep('A',DT$Category,ignore.case = FALSE),]

edited Jun 23 '17 at 06:03

answered Jun 22 '17 at 11:55

Gangesh Dubey

382
1
7

How to filter by a member in column

2 Answers2