= SPSS Add Files =

The '''`ADD FILES`''' command adds the rows of an multiple datasets.
 
<<TableOfContents>>

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== Usage ==

{{{
add files
  /file=fiscalquarter1
  /file=fiscalquarter2
  /file=fiscalquarter3
  /file=fiscalquarter4.
}}}

If a variable is present in more than one dataset, metadata is taken from the first dataset with any (i.e. variable label, value labels, or missing values) metadata set. 



=== File ===

Each '''`/FILE`''' subcommand takes one of:

 * a star (`*`) indicating the active data set
 * the name of a data set
 * a filename or [[SPSS/FileHandle|file handle]]

If the active dataset is included in a join and referenced by a star (`*`), that dataset will be modified in-place by the join.

If the active dataset is included in a join and referenced by name, the final dataset will retain the name.

If the active dataset is not included, the final dataset is unnamed and becomes the active dataset.



=== Rename ===

The '''`/RENAME`''' subcommand applies [[SPSS/RenameVariables|renames]] to the `/FILE` subcommand preceding it.

These renames take place before the datasets are combined. 



=== By, First, and Last ===

The '''`/BY`''' subcommand causes the final dataset to be sorted by a key variable. Each dataset must be presorted by the key variables.

The '''`/FIRST`''' and '''`/LAST`''' subcommands append flag variables that mark the first and last matches by the key variables.

Together, these options can be used to mark the sequence of cases within a group.

{{{
add files
 /file=*
 /by id
 /first=PrimaryFirst
 /last=PrimaryLast.
do if PrimaryFirst=1.
  compute MatchSequence = 1 - PrimaryLast.
else.
  compute MatchSequence = MatchSequence + 1.
end if.
leave MatchSequence.
}}}



=== Keep and Drop ===

The '''`/KEEP`''' and '''`/DROP`''' subcommands specify a list of variables to keep or drop from the final dataset.

Any variable created by a `/IN`, `/FIRST`, or `/LAST` subcommand cannot be dropped.

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== Data Model ==

The `ADD FILES` command reads all datasets and data files named on `/FILE` subcommands.

Execution of the `ADD FILES` command is deferred until the active dataset is read, or until one of the [[SPSS/Execute|EXECUTE]], [[SPSS/FileIO|SAVE]], or [[SPSS/SortCases|SORT CASES]] commands are used.

The `ADD FILES` command recognizes [[SPSS/Filter|FILTER]] status and preserves it, although filtered cases are included in the final dataset.

The `ADD FILES` command deactivates [[SPSS/Weight|WEIGHT]] status.

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== See also ==

[[https://www.gnu.org/software/pspp/manual/html_node/ADD-FILES.html|PSPP manual for ADD FILES]]



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