Is there any way to do partial String matching in R?

Question

I have 2 data frames. First has more number of rows and one ID column "ALP23456" and other related columns. Second has lesser number of rows and the ID value is present as a comment "ALP23456 done on 26th March". This is a free text and no pattern decipherable.

Problem: I want to reference ID column from Data Frame 1 into Data Frame 2 Text column to get some information from Data frame 2. Facing issue as it is not an exact match.

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Solution I want: enter image description here

Possible duplicate of: https://stackoverflow.com/questions/32914357/dplyr-inner-join-with-a-partial-string-match — Tim Biegeleisen, Mar 20 '19 at 04:58
kindly share the two dataframes in r code or by using `dput` — Lunalo John, Mar 20 '19 at 05:06

Lunalo John · Accepted Answer · 2019-03-20T07:01:45.150

0

I have used regular expression and merging of the two dataframes as shown below:

library(stringr)
library(dplyr)

df2$ID <- str_trim(str_extract(df2$Text, pattern = "Q\\S*|A\\S*"))
df <- left_join(df1, df2, by = "ID")

edited Mar 20 '19 at 07:01

answered Mar 20 '19 at 06:31

Lunalo John

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Can you update how to extract : 4 characters(can be from a-z) "_" 9 numeric values. example - NQRT_876789567 (actual format of ID) – Koyeli Mar 20 '19 at 09:31
replace the pattern with `"[A-Z]{4}_[0-9]{9}"` as shown below: `df2$ID – Lunalo John Mar 20 '19 at 09:40
Can I put an OR operator as well in pattern? If for example there are 2 formats like ACB_765876567 and ACBH_765456789 – Koyeli Mar 20 '19 at 09:45
Yes, It is possible to use or operator. It is similar to r syntax in r `|` – Lunalo John Mar 20 '19 at 09:48
In this case you can specify the minimum and maximum since only alpha part is changing :`df2$ID – Lunalo John Mar 20 '19 at 09:49

Is there any way to do partial String matching in R?

1 Answers1