CODEWITHSUNDEEP
sqlr
user3422637
user3422637

Reputation: 4229

What is the R equivalent of SQL's "LIKE '%searched_word%'"?

How would I check if a particular word is contained in the text of a field in my dataset using R.

In SQL, we can use the LIKE comparison operator. For example,

SELECT * FROM schools WHERE name LIKE '%Public School%'

If I had to do the same thing in R, how would I do that?

Upvotes: 4

Views: 12379

Answers (4)

Adam Lee Perelman
Adam Lee Perelman

Reputation: 890

I think the following might answer the question in a simple way.

its a merge of the %in% and %like% function

'%inlike%'<-function(namevec1,namevec2){
  temp1<-strsplit(namevec1," ")
  temp2<-strsplit(namevec2," ")
  ifelse(is.na(charmatch(temp1,temp2)),F,T)
}

namevec1<-c("ffd","ff","hello_world")
namevec2<-c("ffde","ff ","hello_wor")

namevec1 %inlike% namevec2

[1] TRUE TRUE FALSE

namevec2 %inlike% namevec1

[1] FALSE TRUE TRUE

(please note the white space difference)

Upvotes: 0

Tyler Rinker
Tyler Rinker

Reputation: 109874

The qdap package has a convenience wrapper for agrep that allows you to search all fields in a data frame or specific fields:

schools <- data.frame(
    rank = 1:20, 
    schools = rep(c("X Public School", "Y Private School"), 10)
)


library(qdap)
Search(schools, "Public School", "schools")

##    rank         schools
## 1     1 X Public School
## 3     3 X Public School
## 5     5 X Public School
## 7     7 X Public School
## 9     9 X Public School
## 11   11 X Public School
## 13   13 X Public School
## 15   15 X Public School
## 17   17 X Public School
## 19   19 X Public School

Upvotes: 0

Chris Bail
Chris Bail

Reputation: 307

In Base R one can use %in% to subset data e.g. dataframe[dataframe$variable %in% dataframe2$variable2]

Upvotes: 0

G. Grothendieck
G. Grothendieck

Reputation: 269664

Given

schools <- data.frame(rank = 1:20, 
                 name = rep(c("X Public School", "Y Private School"), 10))

try this:

subset(schools, grepl("Public School", name))

or this:

schools[ grep("Public School", schools$name), ]

or this:

library(sqldf)
sqldf("SELECT * FROM schools WHERE name LIKE '%Public School%'")

or this:

library(data.table)
data.table(schools)[ grep("Public School", name) ]

or this:

library(dplyr)
schools %>% filter(grepl("Public School", name))

Upvotes: 10

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