mvl_merge: Merge two MVL data frames and write the result

In RMVL: Mappable Vector Library for Handling Large Datasets

Merge two MVL data frames and write the result

Description

Merge two MVL data frames and write the result

Usage

mvl_merge(
  MVLHANDLE,
  df1,
  df2,
  name = NULL,
  by = NULL,
  by.x = by,
  by.y = by,
  suffixes = c(".x", ".y"),
  only.columns.x = NULL,
  only.columns.y = NULL
)

Arguments

MVLHANDLE	a handle to MVL file produced by mvl_open()
df1	a data.frame stored in MVL file
df2	a data.frame stored in MVL file
name	if specified add a named entry to MVL file directory
by	list of columns to use as key
by.x	list of columns to use as key for df1
by.y	list of columns to use as key for df1
suffixes	rename columns with identical names using these suffixes
only.columns.x	only copy these columns from df1
only.columns.y	only copy these columns from df2

Value

an object of class MVL_OFFSET that describes an offset into this MVL file. MVL offsets are vectors and can be concatenated. They can be written to MVL file directly, or as part of another object such as list.

See Also

mvl_hash_vectors, mvl_find_matches, mvl_group, mvl_find_matches, mvl_indexed_copy, mvl_order_vectors, mvl_fused_write_objects

Examples

## Not run: 
Mtmp<-mvl_open("tmp_a.mvl", append=TRUE, create=TRUE)
mvl_write_object(Mtmp, data.frame(x=rep(c("a", "b"), 50), y=1:100), "df1")
mvl_write_object(Mtmp, data.frame(x=rep(c("b", "c"), 50), y=runif(100), z=21:120), "df2")
Mtmp<-mvl_remap(Mtmp)
mvl_merge(Mtmp, Mtmp$df1, Mtmp$df2, by.x="y", by.y="z", only.columns.y=c("x"), name="df_merged")
Mtmp<-mvl_remap(Mtmp)
print(Mtmp$df_merged[1:10,])

## End(Not run)

RMVL documentation built on Feb. 23, 2025, 3:01 a.m.