I want to create an object in R, which will contain one string, with a few variables (in my case it is file path). When I try to use paste to concatenate the file paths I can see only one last variable instead of all variables in one string. I use next code:
for(i in seq_len(nrow(samples))) {
lib = samples$conditions[i]
txtFile = file.path(lib, "hits.txt")
testfiles = paste(txtFile, sep = ',')
}
print(testfiles)
and get something like
cond/hits.txt,
instead of
cond/hits.txt,cond1/hits.txt,cond2/hits.txt and so on
Thank you very much for help
Related
Let's say we have a url in R like:
url <- 'http://google.com/maps'
And the objective is to change the 'maps' part of it. I'd like to write a function where basically I can just input something (e.g. 'maps', 'images'), etc., and the relevant part of the url will automatically change to reflect what I'm typing in.
Is there a way to do this in R, where part of the url can be changed by typing something into a function?
Thanks!
You have to store the part you type into a variable and paste this to the base URL:
base_url <- "http://google.com/"
your_extension <- "maps"
paste0(base_url, your_extension)
[1] "http://google.com/maps"
If you have to start with a fixed URL, use sub to replace the last part:
sub("\\w+$", 'foo', url)
# "http://google.com/foo"
You can use dirname to remove the last part of the URL and paste it with additional custom string.
change_url_part <- function(base_url, string) {
paste(dirname(base_url), string, sep = '/')
}
change_url_part('http://google.com/maps', 'images')
#[1] "http://google.com/images"
I am using Octave 5.1.0 on Windows 10 (x64). I am parsing a series of directories looking for an Excel spreadsheet in each directory with "logbook" in its filename. The problem is these files are created by hand and the filenaming isn't consistent: sometimes it's "LogBook", other times it's "logbook", etc...
It looks like the string passed as input to the dir function is case-sensitive so if I don't have the correct case, dir returns an empty struct. Currently, I am using the following workaround, but I wondered if there was a better way of doing this (for a start I haven't captured all possible upper/lower case combinations):
logbook = dir('*LogBook.xls*');
if isempty(logbook)
logbook = dir('*logbook.xls*');
if isempty(logbook)
logbook = dir('*Logbook.xls*');
if isempty(logbook)
logbook = dir('*logBook.xls*');
if isempty(logbook)
error(['Could not find logbook spreadsheet in ' dir_name '.'])
end
end
end
end
You need to get the list of filenames (either via readdir, dir, ls), and then search for the string in that list. If you use readdir, it can be done like this:
[files, err, msg] = readdir ('.'); # read current directory
if (err != 0)
error ("failed to readdir (error code %d): %s", msg);
endif
logbook_indices = find (cellfun (#any, regexpi (files, 'logbook'));
logbook_filenames = files(logbook_indices);
A much less standard approach could be:
glob ('*[lL][oO][gG][bB][oO][kK]*')
Been going around for hours with this. My 1st question online on R. Trying to creat a function that contains a loop. The function takes a vector that the user submits like in pollutantmean(4:6) and then it loads a bunch of csv files (in the directory mentioned) and binds them. What is strange (to me) is that if I assign the variable id and then run the loop without using a function, it works! When I put it inside a function so that the user can supply the id vector then it does nothing. Can someone help ? thank you!!!
pollutantmean<-function(id=1:332)
{
#read files
allfiles<-data.frame()
id<-str_pad(id,3,pad = "0")
direct<-"/Users/ped/Documents/LearningR/"
for (i in id) {
path<-paste(direct,"/",i,".csv",sep="")
file<-read.csv(path)
allfiles<-rbind(allfiles,file)
}
}
Your function is missing a return value. (#Roland)
pollutantmean<-function(id=1:332) {
#read files
allfiles<-data.frame()
id<-str_pad(id,3,pad = "0")
direct<-"/Users/ped/Documents/LearningR/"
for (i in id) {
path<-paste(direct,"/",i,".csv",sep="")
file<-read.csv(path)
allfiles<-rbind(allfiles,file)
}
return(allfiles)
}
Edit:
Your mistake was that you did not specify in your function what you want to get out from the function. In R, you create objects inside of function (you could imagine it as different environment) and then specify which object you want it to return.
With my comment about accepting my answer, I meant this: (...To mark an answer as accepted, click on the check mark beside the answer to toggle it from greyed out to filled in...).
Consider even an lapply and do.call which would not need return being last line of function:
pollutantmean <- function(id=1:332) {
id <- str_pad(id,3,pad = "0")
direct_files <- paste0("/Users/ped/Documents/LearningR/", id, ".csv")
# READ FILES INTO LIST AND ROW BIND
allfiles <- do.call(rbind, lapply(direct_files, read.csv))
}
ok, I got it. I was expecting the files that are built to be actually created and show up in the environment of R. But for some reason they don't. But R still does all the calculations. Thanks lot for the replies!!!!
pollutantmean<-function(directory,pollutant,id)
{
#read files
allfiles<-data.frame()
id2<-str_pad(id,3,pad = "0")
direct<-paste("/Users/pedroalbuquerque/Documents/Learning R/",directory,sep="")
for (i in id2) {
path<-paste(direct,"/",i,".csv",sep="")
file<-read.csv(path)
allfiles<-rbind(allfiles,file)
}
#averaging polutants
mean(allfiles[,pollutant],na.rm = TRUE)
}
pollutantmean("specdata","nitrate",23:35)
I have a data frame and a text variable containing the name of this data frame:
adsl = data.frame(a=2, b=7, w=17)
ds_name = "adsl"
I want to save my data frame from the workspace to the file named "dest_file". The code should be wrapped into a function get_r()
with the data frame name as an argument:
get_r(ds_name="adsl")
So I need to avoid using the explicit name "adsl" inside the code.
The following works almost correctly but the resulting data frame is called "temp_dataset", not "adsl":
get_r = function(ds_name){
temp_dataset = eval(parse(text=ds_name))
save(temp_dataset, file = "dest_file")
}
Here is another option which works wrong (the text string is being saved, not the data frame):
get_r = function(ds_name){
save(ds_name, file = "dest_file")
}
What should I do to make R just execute
save(adsl, file="dest_file")
inside the function? Thank you for any help.
Try
save(list = ds_name, file = "dest_file")
The list argument in save() allows you to pass the name of the data as a character string. See help(save) for more.
I try to group by my customize movieLense dataset
groupBy<- data.table(unifiedTbl)
x<- groupBy[,list(rating=sum(rating)
,Unknown=sum(unknown)
,Action=sum(Action)
,Adventure = sum(Adventure)
,Animation = sum(Animation)
,"Children's" = sum(Children's)
),by=list(user_id,age,occupation)]
but because of Children's I received some error which related to specified character
If I remove below part of my code every things is OK
,"Children's" = sum(Children's)
Now my question is how can I address to this column with full name?
how can I fix my codes?
You can use backticks with names that aren't valid syntax:
`Children's` = sum(`Children's`)
And of course, I'd recommend creating valid names instead:
setnames(groupBy, make.names(names(groupBy)))