if statement - error in if() argument is of length zero in R -
this code
`
region<-"arlington"
data<-read.csv("city_markets.csv")
for(i in 1:length(data[[1]])){
if(grep(region,as.character(data[[3]][i]),ignore.case=true)==1){
for(j in 1:length(data)){ write(data[[j]][i],"analyzed.txt",append=true) } }
} `
now i'm trying here i'm accessing csv's column(3rd one) , comparing region specified! keep getting error
error in if (grep(region, as.character(data[[3]][i]), ignore.case = true) == :
argument of length zero
to detail bit comment , @adii_ 's :
when use grep
, result "position" of elements fulfill condition... "nothing" if there no match (hence error message).
using grepl
, you'll true or false, can use in if
statement.
as length(grep(...))
, result 0
if there no match, corresponding false
if
statement, or positive integer (1
in case because you're testing 1 element), if there match, corresponding true
if
statement.
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