RData files are used to store multiple R objects within a single file. Rda is a short form of RData.
To save multiple objects into RData file, we use the save() function.
save(a, b, c, file = "myobjects.RData")
To save all the objects in the workspace, we use the save.image() function.
save.image(file = "data/projectimage.RData")
To load all of the objects in the workspace from an Rds file, we use the load function.
load(file = "data/projectimage.RData")
Rds files store a single R object. According to R documentation:
These functions provide the means to save a single R object to a connection (typically a file) and to restore the object, quite possibly under a different name. This differs from saving and load, which save and restore one or more named objects into an environment. They are widely used by R itself, for example, to store metadata for a package and to store the help.search databases: the ".rds" file extension is most often used.
saveRDS(object, file = "", ascii = FALSE, version = NULL,
compress = TRUE, refhook = NULL)
readRDS(file, refhook = NULL)
R object to serialize.
a connection or the name of the file where the R object is saved to or read from.
a logical. If TRUE or NA, an ASCII representation is written; otherwise (default), a binary one is used. .
the workspace format version to use. NULL specifies the current default version (3). The only other supported value is 2, the default from R 1.4.0 to R 3.5.0.
a logical specifying whether saving to a named file is to use "gzip" compression, or one of "gzip", "bzip2" or "xz" to indicate the type of compression to be used. Ignored if the file is a connection.
a hook function for handling reference objects.
To know more about Rds files click here.