I have two part question, both concerns working with data frames names:
I want to concatenate two dfs names with separator, for example: df1 and df2 to be "df1_&_df2"
I want make R to read data frame name as character in quotation marks so my df is called df1 and I in certain parts of my code I want it to be "df1".
When it come to 1st part I tried paste but it pasted entire data in both dfs and names concerns column names.
In the 2nd issue, being able to make R understand df name as quotation marked word is very handy in code for more complex charts, I simply put dfs into code and R makes chart title out of it. I understand there is very simple workaround here, I can create list of names manually list=c("df1", "df2") and then just use function get in places where I need to refer to content of data frame instead of its name, but it seems little inconvenient in the long run. Is there any function in R which output is just df name? Something that looks like GiveMeName(df) and the output is "df"? (I wrote this in normal font intentionally, so no one would thought this is real function)
For #1, you'll have to give a use case for me to understand your goal.
For #2, you can use deparse(substitute(df1)). Here's an example:
plot_and_title <- function(df1) {
data_name <- deparse(substitute(df1))
plot(df1[[1]], df1[[2]], main = data_name)
}
plot_and_title(mtcars)
Adding on to the answer by #Nathan Werth, you can concatenate names using:
paste(deparse(substitute(df1)), deparse(substitute(df2)), sep="_&_")
Related
forest area to the I want to add a column name (say ForestAreaPerPopn) to find the ratio of forest area to the population(represented by variable Total below) residing. The data contains the following variables and their values.
How can I add a column named ForestAreaPerPopn in Table****ForestAreaPerPop (shown below) so that the column contains the data calculated as ratio of forest area to Total.
Too long for a comment.
You have a couple of problems. First, your column names have spaces and other special characters. This is allowed but creates all kinds of problems later. I suggest you do something like:
colnames(ForestAreaPerPop) <- gsub(' |\\(|\\)', '_', colnames(ForestAreaPerPop))
This will replaces any spaces, left or right parens in the colnames with '_'.
Then, something like:
ForestAreaPerPop$n <- with(ForestAreaPerPop, Forest_Area_in_ha/Total)
should give you what you want.
Some advice: long table names and column names may seem like a good idea, but you will live to regret it. Make them short but meaningful (easier said than done).
This is probably a basic question, but why does R think my vector, which has a bunch of words in it, are numbers when I try to use these vectors as column names?
I imported a data set and it turns out the first row of data are the column headers that I want. The column headers that came with the data set are wrong ones. So I want to replace the column names. I figured this should be easy.
So what I did was I extracted the first row of data into a new object:
names <- data[1,]
Then I deleted the first row of data:
data <- data[-1,]
Then I tried to rename the column headers with the "names" object:
colnames(data) <- names
However, when I do this, instead of changing my column names to the words within the names object, it turns it into a bunch of numbers. I have no idea where these numbers come from.
Thanks
You need to actually show us the data, and the read.csv()/read.table() command you used to import.
If R thinks your numeric column is string, it sounds like that's because it wrongly includes the column name, i.e. you omitted header=TRUE in your read.csv()/read.table() import.
But show us your actual data and commands used.
I think this one is easy but I still can't figure it out and I really need help with this. I've looked everywhere but still couldn't find it.
Let's say I have this vector:
filenames <- c("fn1", "fn2", "fn3")
And I want to associate them with an dataframe that is created according to a function, that is generated at that time
df|name from filenames[i]| <- df
so it would return these dataframes
dffn1
dffn2
dffn3
I hope I made myself clear. My problem is create a new data frame and name it according to a list or whatever, in a for loop.
You can use assign to achieve what you want.
for(nms in filenames){
assign(paste('df',nms,sep=''), df) }
I want to create a funtion that creates new data frames using some variables from other data frames. For that I thing I need to print the variable names in my own function somehow.
The variables come from two data frames (asd and tetracam) which have six variables in common, the bands "w530", "w550", "w570", "670", "w700" and "w800". So, I want to create six data frames, one for each band. One by one I could write like this:
# Band w530
w530<-data.frame(tetracam$filename,tetracam$time,tetracam$type,tetracam$w530,asd$w530)
names(w530)<-c("filename","time","type","tetracam","asd")
w530<-w530[order(w530$time),]
It works fine but I'd like to do it as a function in order to run for all bands. I thought I have to replace all the w530 in the code above for a dinamic object. As I thought of using some of the apply family. So, I first created a list with the names of my common variables:
bands<-c("w530","w550","w570","670","w700","w800")
Then, I tried several ways, for example, using cat or sprintf that would use the strings from the list to fill my function. But it didn't work. Actually, I'm not sure which apply family function I would use. If it's possible to use any in this case:
my.fun<- function(band){
sprintf("%s<-data.frame(tetracam$filename,tetracam$time,tetracam$type,asd$%s,tetracam$%s)",band,band,band)
sprintf("names(%s)<-c('filename','time','type','asd','tetracam')",band)
sprintf("%s[order(%s$time),]",band,band)
}
Any help is appreciated.
Trick is to access data.frame column using df[varName] idiom.
fun1 <- function(band, tetracam, asd){
df<-data.frame(tetracam$filename,tetracam$time,tetracam$type,tetracam[band],asd[band])
names(df)<-c("filename","time","type","tetracam","asd")
df<-df[order(df$time),]
return(df)
}
for (band in bands){
single_band_df <- fun1(band, tetracam, asd)
}
This is definitely a rookie question but I'm not finding an answer for this (maybe because of my wording) so here goes:
I'm reading a data frame into R studio (csv file) that has 24 columns with headers. There are only numbers in these columns (they're essentially concentrations of several chemicals). It's called all. I need to use them as numeric vectors. When I read them in and type
is.numeric(all[,1])
I get
TRUE
When I type
is.numeric(all[1])
I get
FALSE
I think this is because R interprets the header as a factor. I also tried reading in a table without headers and with headers=FALSE, but R renames it to V1, V2 etc so the result ends up being the same.
I need to work with functions where I invoke something like all[2:24]. How can I go about to make R either "not see" the header or remove it altogether?
Thanks for the answers!
PS: the dataframe I am using (without headers - if it had headers, it would just have names instead of V1, V2, etc) is something like this:
This is a subset from the first column, not the first row.
all[,1]) #subset first column
The following is subset of first row
all[1,]) #subset first row (headers of df not included)
To give columnames
colnames(all) <- c("col1","col2")
Your assumption is wrong. You have a data.frame and all[1] does list subsetting, which results in a data.frame, which is not a vector, and not a numeric vector in particular.
You should study help("[") and An Introduction to R.