[R] Identifying columns with specific character

[Jeff Newmiller]

Your message came through all messed up because you did not tell your email program to use plain text format. This at best delays a responds and at worst prevents us from understanding your question as you intended.

1) The columns became factors when you created the data frame because you did not include the stringsAsFactors=FALSE argument. The apply function does NOT turn the columns to factors. 

2) Your use of "x <-" in your apply function is misleading, though not destructive. Just omit that assignment. 

dta2 <- apply(My.Data, 2, function (x) gsub("\\$", "", x)))

On April 18, 2018 4:23:09 PM CDT, Farnoosh Sheikhi via R-help <r-help using r-project.org> wrote:
>Hello,
>I have a data frame with 400 columns and wanted to filter character
>columns with "$" in it.For example: >  x <- c("$5", "$89", "$10",
>"$34")  >  y <- c(1:4)>  My.Data <- data.frame (x,y)> My.Data    x y1 
>$5 12 $89 23 $10 34 $34 4
>I want to detect the columns with $ and remove the $ from the selected
>columns.I have tried apply(My.Data, 2, function (x) any(grepl("$", x)))
>but it's not really working.Or:  apply(My.Data, 2,
>function(x){x<-gsub("\\$", "", x)}) works but it turns all the columns
>to a factor.
>Thanks.
>	[[alternative HTML version deleted]]
>
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-- 
Sent from my phone. Please excuse my brevity.