merge {base} | R Documentation |
Abbreviation: mrg A horizontal merge combines data frames horizontally, that is, adds variables (columns) to an existing data frame, such as with a common shared ID field. Performs the horizontal merge based directly on the standard R merge function. The vertical merge is based on the rbind function in which the two data frames have the same variables but different cases (rows), so the rows.
# Make a data frame mapping story numbers to titles stories Merge the two data frames merge (stories, data, 'storyid. The common key variable is surname. We can merge both data and check if the dimensionality is 7x3. We add stringsAsFactors=FALSE in the data frame because we don't want R to convert string as factor, we want the variable to be treated as character. R Documentation. Merge Two Data Frames. Merge two data frames by common columns or row names. Merge(x, y, by, by.x, by.y, sort = TRUE) Arguments. When a single column header is split across cells, merge the cells with mergerows or mergecols. If a column header 'Mean GDP' is split over two cells, where the top cell has the value 'Mean' and the bottom cell has the value 'GDP', then mergerows will combine them into a single cell with the value 'Mean GDP'. Mergerows keeps the top cell, and mergecols keeps the left-most.
Merge Two Data Frames
Description
Merge two data frames by common columns or row names.
Usage
Arguments
x, y | data frames, or objects to be coerced to one |
by, by.x, by.y | specifcations of the common columns. See Details. |
sort | logical. Should the results be sorted on the by columns? |
Details
By default the data frames are merged on the columns with names they both have, but separate specifcations of the columns can be given by
by.x
and by.y
. Columns can be specified by name, number or by a logical vector: the name 'row.names'
or the number 0
specifies the row names. The rows in the two data frames that match on the specified columns are extracted, and joined together. If there is more than one match, all possible matches contribute one row each. If the remaining columns in the data frames have any common names, these have
'.x'
and '.y'
appended to make the names of the result unique. Value
A data frame. The rows are by default lexicographically sorted on the common columns, but are otherwise in the order in which they occurred in
x
. The columns are the common columns followed by the remaining columns in x
and then those in y
. If the matching involved row names, an extra column Row.names
is added at the left, and in all cases the result has no special row names.![Merge Merge](/uploads/1/3/7/5/137531291/438246801.png)
R Merge By Multiple Columns
See Also
data.frame
, by
, cbind