How can i remove rows by condition (initial letters) in r?

Question

Date  <- c(2000-01-01, 2000-02-02, ... )   
Abbreviation  <- c("TR_10", "SR_10", "SR_9", "FR_7", "SR_7", ...)       
Value   <- c(1.2, 1.3, 1.4, 1.8, ... )
Data <- cbind(Date,Abbreviation,Value)

How can I remove all rows, which haven't the abbreviation (initial letters) "SR_"?

Thank you!

score 1 · Answer 1 · answered Mar 31 '20 at 21:06

1

We can use substr

subset(Data, substr(Abbreviation, 1, 3) == "SR_")

data

Data <- data.frame(Date, Abbreviation, Value, stringsAsFactors = FALSE)

answered Mar 31 '20 at 21:06

akrun

874,273
37
540
662

Doğanay Özese · Accepted Answer · 2020-03-31T21:32:56.017

1

You can also convert the data to a data frame and simply use filter() by the dpylr package. In addition to your code, you can have a solution like this:

Data <- data.frame(Data)

Then assign the filtered data to another dataframe.

DataFiltered <- Data %>% filter(Abbreviation %like% "SR_")

Similarly, you can use str_detect() function from stringr package for filtering. This works better, if there is a possibility that Abbreviation has entities having 'SR_' not only as the first 3 characters. You can use RegEx to specify that each entity in filtered data must have Abbreviation starting with 'SR_'.

DataFiltered <- Data %>% filter(str_detect(Abbreviation, pattern = "^SR_"))

edited Mar 31 '20 at 21:32

answered Mar 31 '20 at 21:24

Doğanay Özese

36
3

Where does the `%like%` operator come from? – camille Mar 31 '20 at 23:37
`%like%` operator comes from the `data.table` package, again. It is actually a similar form of `grep()` family from base R. – Doğanay Özese Apr 01 '20 at 11:18

score 0 · Answer 3 · answered Mar 31 '20 at 21:42

0

Maybe you can try

Data[grep("^SR_",Data[,"Abbreviation"]),]

answered Mar 31 '20 at 21:42

ThomasIsCoding

96,636
9
24
81

How can i remove rows by condition (initial letters) in r?

3 Answers3

data