CODEWITHSUNDEEP
rsubstringwildcard
user2543622
user2543622

Reputation: 6756

r substring wildcard search to find text

I have a data.frame column that has values such as below. I want to use each cell and create two columns- num1 and num2 such that num1=everything before "-" and num2=everything between "-" and "."

I am thinking of using gregexpr function as shown here and write a for loop to iterate over each row. Is there a faster way to do this?

60-150.PNG
300-12.PNG

employee <- c('60-150.PNG','300-12.PNG')
employ.data <- data.frame(employee)

Upvotes: 3

Views: 521

Answers (5)

akrun
akrun

Reputation: 887088

Try

library(tidyr)
extract(employ.data, employee, into=c('num1', 'num2'),
                    '([^-]*)-([^.]*)\\..*', convert=TRUE)
#   num1 num2
#1   60  150
#2  300   12

Or

library(data.table)#v1.9.5+
setDT(employ.data)[, tstrsplit(employee, '[-.]', type.convert=TRUE)[-3]]
#    V1  V2
#1:  60 150
#2: 300  12

Or based on @rawr's comment

 read.table(text=gsub('-|.PNG', ' ', employ.data$employee),
           col.names=c('num1', 'num2'))
 #   num1 num2
 #1   60  150
 #2  300   12

Update

To keep the original column

extract(employ.data, employee, into=c('num1', 'num2'), remove=FALSE,
        '([^-]*)-([^.]*)\\..*', convert=TRUE)
#    employee num1 num2
#1 60-150.PNG   60  150
#2 300-12.PNG  300   12

Or

 setDT(employ.data)[, paste0('num', 1:2) := tstrsplit(employee, 
             '[-.]', type.convert=TRUE)[-3]]
 #     employee num1 num2
 #1: 60-150.PNG   60  150
 #2: 300-12.PNG  300   12

Or

 cbind(employ.data, read.table(text=gsub('-|.PNG', ' ', 
     employ.data$employee),col.names=c('num1', 'num2')))
 #    employee num1 num2
 #1 60-150.PNG   60  150
 #2 300-12.PNG  300   12

Upvotes: 5

David Arenburg
David Arenburg

Reputation: 92282

Another option using stringi

library(stringi)
data.frame(type.convert(stri_split_regex(employee, "[-.]", simplify = TRUE)[, -3]))
#    X1  X2
# 1  60 150
# 2 300  12

Upvotes: 3

dimitris_ps
dimitris_ps

Reputation: 5951

Or with the simple gsub.

gsub("-.*", "", employ.data$employee) # substitute everything after - with nothing
gsub(".*-(.*)\\..*", "\\1", employ.data$employee) #keep only anything between - and .

Upvotes: 2

A5C1D2H2I1M1N2O1R2T1
A5C1D2H2I1M1N2O1R2T1

Reputation: 193517

You can try cSplit from my "splitstackshape" package:

library(splitstackshape)
cSplit(employ.data, "employee", "-|.PNG", fixed = FALSE)
#    employee_1 employee_2
# 1:         60        150
# 2:        300         12

Since you mention gregexpr, you can probably try something like:

do.call(rbind, 
        regmatches(as.character(employ.data$employee), 
                   gregexpr("-|.PNG", employ.data$employee), 
                   invert = TRUE))[, -3]
     [,1]  [,2] 
[1,] "60"  "150"
[2,] "300" "12"

Upvotes: 3

economy
economy

Reputation: 4251

The strsplit function will give you what you're looking for, output to a list.

employee <- c('60-150.PNG','300-12.PNG')
strsplit(employee, "[-]")

##Output:

[[1]]
[1] "60"      "150.PNG"

[[2]]
[1] "300"    "12.PNG"

Note the second argument to strsplit is a regex value, not just a character to split on, so more complicated regexp can be used.

Upvotes: 1

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