Data Import and Export

General data loading

Note

loadd and saved are recommended for most cases when working with the following file types:

  • GAUSS, SAS, Stata and SPSS datasets.
  • CSV and Excel files with variable names in the first row.
getHeaders Returns the variable names from a dataset as a string array.
loadd Loads data into a GAUSS dataframe. The supported dataset types are CSV, Excel (XLS, XLSX), HDF5, GAUSS Matrix (FMT), GAUSS Dataset (DAT), Stata (DTA) and SAS (SAS7BDAT, SAS7BCAT).
saved Writes a matrix or dataframe in memory to a dataset in a specified format.

CSV and delimited text files

csvReadM Reads numeric data from a CSV file into a GAUSS matrix.
csvReadSA Reads data from a CSV file into a GAUSS string array.
csvWriteM Write the contents of a GAUSS matrix to a CSV file.

Spreadsheets (Excel files)

xlsGetSheetCount Returns the number of sheets in an Excel® spreadsheet.
xlsGetSheetSize Returns the size (rows and columns) of a specified sheet in an Excel® spreadsheet.
xlsGetSheetTypes Gets the cell format types of a row in an Excel® spreadsheet.
xlsMakeRange Builds an Excel® range string from a row/column pair.
xlsReadM Reads from an Excel® spreadsheet into a GAUSS matrix.
xlsReadSA Reads from an Excel® spreadsheet into a GAUSS string array.
xlsWrite Writes a GAUSS matrix, string, or string array to an Excel® spreadsheet.

HDF 5 files

h5create Create a HDF5 dataset (.h5).
h5open Open a HDF5 file.
h5read Reads data from a HDF5 file (.h5) into a GAUSS matrix.
h5readAttribute Read attributes from a HDF5 file into GAUSS.
h5write Writes a GAUSS matrix to a HDF5 file.

GAUSS Data Sets

These are the main functions to use for loading and saving GAUSS datasets.

loadd Loads a data set into a GAUSS dataframe.
saved Saves matrices or dataframes to a variety of dataset types.

The following functions use file handles which enable reading and writing partial chunks of a dataset.

close Closes an open data set (.dat file).
closeall Closes all open data sets.
datacreate Creates a file handle to a new, empty GAUSS data set.
dataopen Opens a file handle to a GAUSS data set.
eof Tests for end of file.
getnr Computes number of rows to read per iteration for a program that reads data from a disk file in a loop.
getnrmt Computes number of rows to read per iteration for a program that reads data from a disk file in a loop.
readr Reads rows from open data set.
seekr Moves pointer to specified location in open data set.
tempname Creates a temporary file with a unique name.
typef Returns the element size (2, 4 or 8 bytes) of data in open data set.
writer Writes matrix to a GAUSS dataset using open file handle.

Databases

Database Setup

dbAddDatabase Adds a database to the list of database connections using the driver type or a connection URL.
dbGetDrivers Returns a list of available database drivers.
dbIsDriverAvailable Returns 1 if a specified database driver is available.
dbRemoveDatabase Removes a database connection from the list of open database connections. Frees all related resources.

Database Properties

dbGetConnectOptions Returns the connection options string used for a database connection.
dbGetDatabaseName Returns the name of the database.
dbGetDriverName Returns the name of the connection’s database driver.
dbGetHostName Returns the database connection’s host name.
dbGetPassword Returns a connection’s password.
dbGetNumericalPrecPolicy Returns the default numerical precision policy for a specified database connection.
dbGetPort Returns the database connection’s port number if it has been set.
dbIsOpen Reports whether a specified database connection is open.
dbIsValid Reports whether a specified database connection has a valid driver.
dbSetConnectOptions Sets database-specific options.
dbSetDatabaseName Sets the connection’s database name to name.
dbSetHostName Sets the specified database connection’s host name.
dbSetNumericalPrecPolicy Sets the default numerical precision policy used by queries created on this database connection.
dbSetPassword Sets the database connection’s password.
dbSetPort Sets the specified database connection’s port number.

Database Information

dbGetPrimaryIndex Returns the primary index for the specified table.
dbGetTableHeaders Returns a string array populated with the names of all the fields in a specified table (or view).
dbGetTables Returns the database’s tables, system tables and views.
dbHasFeature Returns a 1 if the database supports the specified feature.

Database Errors

dbGetLastErrorNum Returns numerical information about the last error that occurred on the database.
dbGetLastErrorText Returns text information about the last error that occurred on the database.
dbIsOpenError Reports whether an error occurred while attempting to open the database connection.
dbQueryGetLastErrorNum Returns numerical error information about the last error that occurred (if any) with the last executed query.
dbQueryGetLastErrorText Returns text error information about the last error that occurred (if any) with the last executed query.

Database Connect

dbClose Closes a database connection and destroys any remaining queries.
dbOpen Opens a specified database connection using the current connection values.

Database Transaction

dbCommit Commits a transaction to the database if the driver supports transactions and a dbTransaction() has been started.
dbCreateQuery Process an SQL statement and prepare a query.
dbExecQuery Executes an SQL statement and creates a query.
dbExecQueries Executes an SQL statement and creates a query for multiple rows of data in one function call.
dbRollback Rolls back a transaction on the database.
dbTransaction Begins a transaction on the database.

Query Building

dbQueryBindValue Set the placeholder placeholder to be bound to value val in the prepared statement.
dbQueryGetBoundValue Returns the value for a placeholder in a query.
dbQueryGetBoundValues Returns an Nx2 string array containing the placeholders and their corresponding values in a query.
dbQueryExecPrepared Executes a previously created and prepared query.
dbQueryPrepare Prepares a SQL query for execution.

Query Manipulation

dbQueryClear Clears the result set and releases any resources held by the query. Sets the query state to inactive.
dbQueryFinish Instructs the database driver that no more data will be fetched from this query until it is re-executed.

Query Information

dbQueryCols Returns the number of fields in the record.
dbQueryGetLastInsertID Returns the object ID of the most recent inserted row if supported by the database.
dbQueryGetLastQuery Returns the text of the current query being used.
dbQueryGetNumRowsAffected Reports the number of rows affected by the result’s SQL statement.
dbQueryIsActive Returns 1 if the query is active.
dbQueryIsForwardOnly Reports whether you can only scroll forward through a result set.
dbQueryIsNull Reports whether the current field pointed at by an active query positioned on a valid record is NULL.
dbQueryIsSelect Reports whether the specified query is a SELECT statement.
dbQueryIsValid Reports whether the specified query is positioned on a valid record.
dbQueryRows Returns the size of the result (number of rows returned), or -1 if the size cannot be determined or if the database does not support reporting information about query sizes.
dbQuerySetForwardOnly Sets forward only mode to forward. If forward is true, only ../dbQuerySeekNext and ../dbQuerySeek with positive values, are allowed for navigating the results.

Query Iteration

dbQueryGetPosition Returns the current internal position of the query.
dbQuerySeek Retrieves the record at a specified position, if available, and positions the query on the retrieved record.
dbQuerySeekFirst Retrieves the first record in the result, if available, and positions the query on the retrieved record.
dbQuerySeekLast Retrieves the last record in the result, if available, and positions the query on the retrieved record.
dbQuerySeekNext Retrieves the next record in the result, if available, and positions the query on the retrieved record.
dbQuerySeekPrevious Retrieves the previous record in the result, if available, and positions the query on the retrieved record.

Query Data Retrieval

dbQueryFetchAllM Returns the result set for the current query as a matrix.
dbQueryFetchAllSA Returns the result set for the current query as a string array.
dbQueryFetchOneM Returns a single row as an Nx1 matrix where N is the column count of the SELECT statement.
dbQueryFetchOneSA Returns a single row as a string vector containing the field information for the current query.
dbQueryGetField Returns the value of a specified field in the current record.

General text file manipulation

To read and write data from CSV and delimited text files, see the earlier section.

fcheckerr Gets the error status of a file.
fclearerr Gets the error status of a file, then clears it.
fflush Flushes a file’s output buffer.
fgets Reads a line of text from a file.
fgetsa Reads lines of text from a file into a string array.
fgetsat Reads lines of text from a file into a string array without retaining newlines.
fgetst Reads a line of text from a file without retaining the newline.
fopen Opens a file.
fputs Writes strings to a file.
fputst Writes strings followed by a newline to a file.
fseek Positions the file pointer in a file.
fstrerror Returns an error message explaining the cause of the most recent file I/O error.
ftell Gets the position of the file pointer in a file.
getf Loads an ASCII or binary file into a string.
putf Writes the contents of a string to a file.