| Title: | An R Interface for Raven DataFrames (Beta0) |
| Version: | 0.2.0 |
| Description: | Provides an I/O interface between R data.frames and Raven DataFrames. Defines functions to both read and write DataFrame files, as well as serialize/deserialize data.frames/DataFrames. |
| License: | Apache License (== 2) |
| URL: | https://github.com/raven-computing/rdf |
| Encoding: | UTF-8 |
| Depends: | R (≥ 3.5.0) |
| LazyData: | true |
| RoxygenNote: | 7.1.1 |
| Maintainer: | Phil Gaiser <phil.gaiser@raven-computing.com> |
| Suggests: | testthat (≥ 3.0.0) |
| Config/testthat/edition: | 3 |
| NeedsCompilation: | no |
| Packaged: | 2021-03-15 11:12:42 UTC; kilo52 |
| Author: | Phil Gaiser [aut, cre], Raven Computing [cph] |
| Repository: | CRAN |
| Date/Publication: | 2021-03-17 13:20:02 UTC |
Deserializes the given vector of raw bytes and returns a data.frame object.
Description
The raw vector to be deserialized must represent a Raven DataFrame. That DataFrame is returned as an R data.frame object.
Usage
deserializeDataFrame(bytes)
Arguments
bytes |
The vector of raw bytes to deserialize |
Details
The column types from Raven DataFrames are mapped to the corresponding R types. More specifically, all integer types (byte, short, int, long) are mapped to the R 'integer' type. The floating point types (float, double) are mapped to the R 'double' type. Both string and char types are mapped to the R 'character' type. Booleans are mapped to the R 'logical' type. Binary columns are represented as R 'list' types containing raw vectors.
Value
A data.frame object from the specified raw vector
See Also
readDataFrame() for reading DataFrame (.df)
files directly.
Examples
## Not run:
# deserialize a raw vector representing a DataFrame
df <- deserializeDataFrame(my.raw.vector)
# get the types for all columns
types <- sapply(df, typeof)
## End(Not run)
Reads a DataFrame from the specified file.
Description
The file to be read must be a DataFrame (.df) file. The content of the file is returned as an R data.frame object.
Usage
readDataFrame(filepath)
Arguments
filepath |
The path to the file to read |
Details
The column types from Raven DataFrames are mapped to the corresponding R types. More specifically, all integer types (byte, short, int, long) are mapped to the R 'integer' type. The floating point types (float, double) are mapped to the R 'double' type. Both string and char types are mapped to the R 'character' type. Booleans are mapped to the R 'logical' type. Binary columns are represented as R 'list' types containing raw vectors.
Value
A data.frame object
See Also
deserializeDataFrame() for deserializing vectors
of raw bytes.
writeDataFrame() for writing DataFrame files which can be read
by this function.
Examples
## Not run:
# read a .df file into memory
df <- readDataFrame("/path/to/my/file.df")
# get the types for all columns
types <- sapply(df, typeof)
## End(Not run)
Serializes the specified data.frame object to a vector of raw bytes.
Description
The R data.frame is serialized as a Raven DataFrame. The concrete column types to use for each individual data.frame column can be specified by the 'types' argument.
Usage
serializeDataFrame(df, types = NULL, compress = FALSE, as.nullable = FALSE)
Arguments
df |
The data.frame object to serialize |
types |
The type names for all column types. Must be a vector of character values. May be NULL |
compress |
A logical indicating whether to compress the content of the returned raw vector |
as.nullable |
A logical indicating whether the data.frame should be serialized as a NullableDataFrame, even if it contains no NA values |
Details
The column types of the R data.frame object are mapped to the corresponding Raven DataFrame column types. The following types exist:
| Type name | Description |
| byte | int8 |
| short | int16 |
| int | int32 |
| long | int64 |
| float | float32 |
| double | float64 |
| string | UTF-8 encoded unicode string |
| char | single printable ASCII character |
| boolean | logical value TRUE or FALSE |
| binary | arbitrary length byte array |
By default, if the 'types' argument is not explicitly specified, all values are mapped to the corresponding largest possible type in order to avoid possible loss of information. However, users can specify the concrete type for each column in the DataFrame file to be written. This is done by providing a vector of character values denoting the type name of each corresponding data.frame column. The index of each entry corresponds to the index of the column in the underlying data.frame to persist.
If the specified data.frame object contains at least one NA value, then the serialized DataFrame will represent a NullableDataFrame. If the data.frame contains no NA values, then the serialized DataFrame will represent a DefaultDataFrame, unless the 'as.nullable' argument is set to TRUE.
The logical 'compress' argument specifies whether the serialized DataFrame is compressed.
Value
A raw vector representing the serialized date.frame object
See Also
writeDataFrame() for directly persisting data.frame objects
to the file system
Examples
## Not run:
# get a data.frame
df <- cars
# serialize the data.frame to a raw vector
vec <- serializeDataFrame(df)
# specify the concrete types of all columns
coltypes <- c("float", "double")
# serialize the data.frame to a raw vector with concrete types
serializeDataFrame(df, types = coltypes)
## End(Not run)
Writes the specified data.frame to the specified file.
Description
The R data.frame is persisted as a DataFrame (.df) file. The concrete column types to use for each individual data.frame column can be specified by the 'types' argument.
Usage
writeDataFrame(filepath, df, types = NULL, as.nullable = FALSE)
Arguments
filepath |
The path to the file to write |
df |
The data.frame object to write |
types |
The type names for all column types. Must be a vector of character values. May be NULL |
as.nullable |
A logical indicating whether the data.frame should be persisted as a NullableDataFrame, even if it contains no NA values |
Details
The column types of the R data.frame object are mapped to the corresponding Raven DataFrame column types. The following types exist:
| Type name | Description |
| byte | int8 |
| short | int16 |
| int | int32 |
| long | int64 |
| float | float32 |
| double | float64 |
| string | UTF-8 encoded unicode string |
| char | single printable ASCII character |
| boolean | logical value TRUE or FALSE |
| binary | arbitrary length byte array |
By default, if the 'types' argument is not explicitly specified, all values are mapped to the corresponding largest possible type in order to avoid possible loss of information. However, users can specify the concrete type for each column in the DataFrame file to be written. This is done by providing a vector of character values denoting the type name of each corresponding data.frame column. The index of each entry corresponds to the index of the column in the underlying data.frame to persist.
If the specified data.frame object contains at least one NA value, then the DataFrame file to be persisted will represent a NullableDataFrame. If the data.frame contains no NA values, then the DataFrame file to be persisted will represent a DefaultDataFrame, unless the 'as.nullable' argument is set to TRUE.
Value
The number of bytes written to the specified file
See Also
serializeDataFrame() for serializing data.frame objects
to vectors of raw bytes.
readDataFrame() for reading DataFrame files which have been
previously persisted by this function.
Examples
## Not run:
# get a data.frame
df <- cars
# write the data.frame to a .df file
writeDataFrame("cars.df", df)
# specify the concrete types of all columns
coltypes <- c("float", "double")
# write the data.frame to a .df file with concrete types
writeDataFrame("cars.df", df, types = coltypes)
## End(Not run)