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Accepted
Alejandro Carrera
Asked: 2020-03-12 15:55:30 +0800 CST 2020-03-12 15:55:30 +0800 CST

How to filter lines based on a specified string plus additional text?

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I have a column with text similar to the following:

cadenas <- c("el metro", "dos metrobuses", "pasó en el metro norte", "metro 12", "no")

I'm interested in only getting the elements that strictly have the word "meter", that is, elements 1, 3 and 4.

grepl("metro", cadenas)

Returns TRUE for the first 4 and FALSE for the last. I have tried many combinations to get only the ones that interest me without any success.

cadenas[grepl("metro [[:alnum:]]", cadenas)] #Regresa los elementos 3 y 4 (resultado más cercano al deseado)
cadenas[grepl("\\ metro [[:alnum:]]", cadenas)] #Regresa el elemento 3
cadenas[grepl("\\ metro", cadenas)] #Regresa los elementos 1,2 y 3

I have read many places without finding an answer that satisfies my requirements so any guidance would be greatly appreciated.

r

1 Answers

  1. Best Answer

    You can use the pattern \\b( word boundary / word limit ) to detect metroas a whole word:

    cadenas <- c("el metro", "dos metrobuses", "pasó en el metro norte", "metro 12", "no")
cadenas[grepl("\\bmetro\\b", cadenas)]

[1] "el metro"               "pasó en el metro norte"
[3] "metro 12"
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