I have the following string and 2 dataframes. There are many sets of this configuration (components, fueltypes, etc). I will create one set as an example. If components, fueltypes, etc has no data then I want to fill them as shown below.
Doing this operation is contingent on components, etc not having any data rows.
rocketnum <- "0000"
events_components <- data.frame(unique_event=c("thrust","azimuth","gyro","spin"))
#create empty df with column names but no data
components <- data.frame(rocketnum=character(),
event=character(),
powerlevel=character(),
propellant=character(),
stringsAsFactors=FALSE)
events_components:
components:
and want the following as a result in components:
If I do not misunderstand the question, then you want to populate the components
table using rocketnum
and events_components
, if components
is empty. This could be done by using
if (nrow(components) == 0) {
# extend the empty data frame by the needed number of rows
components[1:nrow(events_components), ] <- NA
components$rocketnum <- rocketnum
components$event <- events_components$unique_event
}
components
rocketnum event powerlevel propellant
1 0000 thrust <NA> <NA>
2 0000 azimuth <NA> <NA>
3 0000 gyro <NA> <NA>
4 0000 spin <NA> <NA>