How to convert original input to index value in R
Thanks for the help. I have an original input file " foo.txt
" and another dictionary
file " dic.csv
" where each line in the dic file is a pair key-value
, the key is one character and the value is another character.
maybe foo.txt :
abcd
dcba
aaaa
and dic.csv :
a 1
b 2
c 3
d 4
I want to convert "foo.txt" to values in the dic file according to the matching key, for example as a result:
1234 4321 1111
Is there an efficient way to do this?
Thank!
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Try
chartr(paste(d1$Col1, collapse=''), paste(d1$Col2, collapse=""), v1)
#[1] "1234" "4321" "1111"
Or instead of two paste
, we can loop through withsapply
v2 <- sapply(d1, paste, collapse='')
chartr(v2[1], v2[2], v1)
#[1] "1234" "4321" "1111"
Or using mgsub
fromqdap
library(qdap)
mgsub(d1$Col1, d1$Col2, v1)
#[1] "1234" "4321" "1111"
or
library(gsubfn)
gsubfn('[abcd]', list(a=1, b=2, c=3, d=4), v1)
#[1] "1234" "4321" "1111"
data
v1 <- c('abcd', 'dcba', 'aaaa')
d1 <- data.frame(Col1= letters[1:4], Col2=1:4, stringsAsFactors=FALSE)
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You can turn the dictionary data.frame
into a named vector and then use indexing:
foo <- c("abcd", "dcba", "aaaa")
dict <- data.frame(key = letters[1:4], value = 1:4)
dict.vec <- setNames(dict$value, dict$key)
sapply(foo, function(x)
paste(dict.vec[strsplit(x, "")[[1]]], collapse = ""))
# abcd dcba aaaa
# "1234" "4321" "1111"
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