My objective is to create an xml object that comprises multiple elements that each contain varying information. A simple example of what the xml object looks like is:
library(xml2)
x1 <- read_xml("<Diag><line level='3' description='a log message'/><line level='3' description='a second log message'/></Diag>")
message(x1)
Which outputs:
<Diag>
<line level="3" description="a log message"/>
<line level="3" description="a second log message"/>
</Diag>
At the moment, I take the information from a data frame called diag. I add the children using a for loop:
library(xml2)
diag <- data.frame(level=c(3,3),description=c('a log message','a second log message'),stringsAsFactors = F)
x2 <- xml_new_root("Diag")
for (i in 1:dim(diag)[1]) {
xml_add_child(.x=x2,.value="line",level=diag$level[i],description=diag$description[i])
}
message(x2)
The xml layout of which is identical to that of x1.
However, this loop is less elegant than I would like it to be, and, for large data frames, can be slow.
My question is: is there any way that I can create multiple children at once using the data in my data frame, by using something akin to apply?
I have tried various options but none were successful and I am not sure I was close enough to post any of these options here. Currently, I am using the xml2 package but if a solution can be found using another package then I'd be open to that also.
Much obliged for any help!
The following seems to be doing what you want, using sapply as requested.
x2 <- xml_new_root("Diag")
sapply(1:dim(diag)[1], function(i) {
xml_add_child(.x=x2,.value="line",level=diag$level[i],description=diag$description[i])
}
)
message(x2)
<?xml version="1.0" encoding="UTF-8"?>
<Diag>
<line level="3" description="a log message"/>
<line level="3" description="a second log message"/>
</Diag>