# R Combine Multiple Rows Into One

Hi This is my first post on this forum, I couldn't find the answer elsewhere, that's why I decided to post it here: I would like to combine multiple rows with the same id, into one. I have a table that has multiple rows, and some of the values are missing. I just need to combine them into a single row by year. I have done it with two data sets. In this case, I only have one data set. What is best way to combine them to a single row? Thanks team in advance! Input table: ID Year Value1 Value2 Value3.

`merge` is a generic function whose principal method is for data frames: the default method coerces its arguments to data frames and calls the `'data.frame'` method.

By default the data frames are merged on the columns with names they both have, but separate specifications of the columns can be given by `by.x` and `by.y`. 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. For the precise meaning of ‘match’, see `match`.

Columns to merge on can be specified by name, number or by a logical vector: the name `'row.names'` or the number `0` specifies the row names. If specified by name it must correspond uniquely to a named column in the input.

If `by` or both `by.x` and `by.y` are of length 0 (a length zero vector or `NULL`), the result, `r`, is the Cartesian product of `x` and `y`, i.e., `dim(r) = c(nrow(x)*nrow(y), ncol(x) + ncol(y))`.

If `all.x` is true, all the non matching cases of `x` are appended to the result as well, with `NA` filled in the corresponding columns of `y`; analogously for `all.y`.

If the columns in the data frames not used in merging have any common names, these have `suffixes` (`'.x'` and `'.y'` by default) appended to try to make the names of the result unique. If this is not possible, an error is thrown.

If a `by.x` column name matches one of `y`, and if `no.dups` is true (as by default), the y version gets suffixed as well, avoiding duplicate column names in the result.

### Excel Combine Rows With Same Value

The complexity of the algorithm used is proportional to the length of the answer.

In SQL database terminology, the default value of `all = FALSE` gives a natural join, a special case of an inner join. Specifying `all.x = TRUE` gives a left (outer) join, `all.y = TRUE` a right (outer) join, and both (`all = TRUE`) a (full) outer join. DBMSes do not match `NULL` records, equivalent to `incomparables = NA` in R.

Source: `R/bind.r`

This is an efficient implementation of the common pattern of`do.call(rbind, dfs)` or `do.call(cbind, dfs)` for binding manydata frames into one.

## Arguments

### R Combine Multiple Rows Into One Row

... Data frames to combine.Each argument can either be a data frame, a list that could be a dataframe, or a list of data frames.When row-binding, columns are matched by name, and any missingcolumns will be filled with NA.When column-binding, rows are matched by position, so all dataframes must have the same number of rows. To match by value, notposition, see mutate-joins. Data frame identifier.When `.id` is supplied, a new column of identifiers iscreated to link each row to its original data frame. The labelsare taken from the named arguments to `bind_rows()`. When alist of data frames is supplied, the labels are taken from thenames of the list. If no names are found a numeric sequence isused instead. One of `'unique'`, `'universal'`, or`'check_unique'`. See `vctrs::vec_as_names()` for the meaning of theseoptions.

## Value

`bind_rows()` and `bind_cols()` return the same type asthe first input, either a data frame, `tbl_df`, or `grouped_df`.

## Details

### R Combine Multiple Rows Into One Row In Excel

The output of `bind_rows()` will contain a column if that columnappears in any of the inputs.