readRDS

readRDS is a base R function that reads a single R object from a file created with saveRDS. It reconstructs the object in memory, preserving its attributes and internal structure. The file argument should be a path to a file or a connection. The function returns the deserialized object, which you typically assign to a variable, for example: obj <- readRDS("path/to/file.rds").

Key points:

- readRDS reads exactly one object. It is the counterpart to saveRDS, which writes a single R object to a file. For multiple objects, use save to create an .RData file and load to restore all objects.

- The object’s name is not stored in the file; the name is chosen by the assignment at read time (unlike the original variable name used when saving).

- The file is often binary and may be compressed depending on how it was written with saveRDS (compression is controlled by the compress argument in saveRDS; readRDS transparently reads the file).

- readRDS preserves object type, attributes, and most internal structures, so data frames, lists, environments, S3/S4 objects, and closures can be restored.

Usage notes:

- Signature: readRDS(file, refhook = NULL). The refhook parameter is rarely used in typical workflows.

- Security: avoid reading RDS files from untrusted sources. Deserialization can pose risks if the data contains crafted objects.

In practice, readRDS is commonly used for persisting a single object between sessions or for transferring a single object across environments, while saveRDS and loadRData provide a broader set of options for multiple objects.