preinstalled.readers: Automatically read data into memory

In johnmyleswhite/ProjectTemplate: Automates the Creation of New Statistical Analysis Projects

Automatically read data into memory

Description

The preinstalled readers are automatically loaded in the list preinstalled.readers. The reader functions will load a data set stored in the data directory into the specified global variable binding. These functions are not meant to be called directly.

Usage

preinstalled.readers

arff.reader(data.file, filename, variable.name)

csv.reader(data.file, filename, variable.name)

csv2.reader(data.file, filename, variable.name)

db.reader(data.file, filename, variable.name)

dbf.reader(data.file, filename, variable.name)

epiinfo.reader(data.file, filename, variable.name)

feather.reader(data.file, filename, variable.name)

file.reader(data.file, filename, variable.name)

mp3.reader(data.file, filename, variable.name)

mtp.reader(data.file, filename, variable.name)

octave.reader(data.file, filename, variable.name)

ppm.reader(data.file, filename, variable.name)

r.reader(data.file, filename, variable.name)

rdata.reader(data.file, filename, variable.name)

rds.reader(data.file, filename, variable.name)

spss.reader(data.file, filename, variable.name)

sql.reader(data.file, filename, variable.name)

stata.reader(data.file, filename, variable.name)

systat.reader(data.file, filename, variable.name)

tsv.reader(data.file, filename, variable.name)

url.reader(data.file, filename, variable.name)

wsv.reader(data.file, filename, variable.name)

xls.reader(data.file, filename, workbook.name)

xlsx.reader(data.file, filename, workbook.name)

xport.reader(data.file, filename, variable.name)

Arguments

data.file	The name of the data file to be read.
filename	The path to the data set to be loaded.
variable.name	The name to be assigned to in the global environment.

Format

An object of class list of length 55.

Details

Some file formats can contain more than one dataset. In this case all datasets are loaded into separate variables in the format <variable.name>.<subset.name>, where the subset.name is determined by the reader automatically.

The sql.reader function will load data from a SQL database based on configuration information found in the specified .sql file. The .sql file must specify a database to be accessed. All tables from the database, one specific tables or one specific query against any set of tables may be executed to generate a data set.

queries can support string interpolation to execute code snippets using mustache syntax (http://mustache.github.io). This is used to create queries that depend on data from other sources. Code delimited is {{...}}

Example: query: SELECT * FROM my_table WHERE id IN ({{ids}}). Here ids is a vector previously loaded into the Global Environment through ProjectTemplate

Examples of the DCF format and settings used in a .sql file are shown below:

Example 1 type: mysql user: sample_user password: sample_password host: localhost dbname: sample_database table: sample_table

Example 2 type: mysql user: sample_user password: sample_password host: localhost port: 3306 socket: /Applications/MAMP/tmp/mysql/mysql.sock dbname: sample_database table: sample_table

Example 3 type: sqlite dbname: /path/to/sample_database table: sample_table

Example 4 type: sqlite dbname: /path/to/sample_database query: SELECT * FROM users WHERE user_active == 1

Example 5 type: sqlite dbname: /path/to/sample_database table: *

Example 6 type: postgres user: sample_user password: sample_password host: localhost dbname: sample_database table: sample_table

Example 7 type: odbc dsn: sample_dsn user: sample_user password: sample_password dbname: sample_database query: SELECT * FROM sample_table

Example 8 type: oracle user: sample_user password: sample_password dbname: sample_database table: sample_table

Example 9 type: jdbc class: oracle.jdbc.OracleDriver classpath: /path/to/ojdbc5.jar (or set in CLASSPATH) user: scott password: tiger url: jdbc:oracle:thin:@myhost:1521:orcl query: select * from emp

Example 10 type: heroku classpath: /path/to/jdbc4.jar (or set in CLASSPATH) user: scott password: tiger host: heroku.postgres.url port: 1234 dbname: herokudb query: select * from emp

Example 11 In this example RSQLite::initExtension() is automatically called on the established connection.

Liam Healy has written extension-functions.c, which is available on http://www.sqlite.org/contrib. It provides mathematical and string extension functions for SQL queries using the loadable extensions mechanism.

type: sqlite dbname: /path/to/sample_database plugin: extension query: SELECT *,STDEV(value1) FROM example_table

Value

No value is returned; the reader functions are called for its side effects.

Functions

• arff.reader(): Read the Weka file format from files with the .arff extension.

• csv.reader(): Read a comma separated values file with the .csv extension.

• csv2.reader(): Read a semicolon separated values file with the .csv2 extension.

  In May 2018, the default behavior of the reader for .csv2 files changed to use R's read.csv2(), where the field separator is assumed to be ';' and the decimal separator to be ','.

• db.reader(): Read a SQlite3 database with a .db file extension.

  If you want to specify a single table or query to execute against the database, move it elsewhere and use a .sql file interpreted by sql.reader.

• dbf.reader(): Read an XBASE file with a .dbf file extension.

• epiinfo.reader(): Read an Epi Info file with a .rec file extension.

• feather.reader(): Read a feather file in Apache Arrow format with a .feather file extension.

• file.reader(): Read an arbitrary file described in a .file file.

  A .file file must contain DCF that specifies the path to the data set and which extension should be used from the dispatch table to load the data set.

  Examples of the DCF format and settings used in a .file file are shown below:

  path: http://www.johnmyleswhite.com/ProjectTemplate/sample_data.csv extension: csv

• mp3.reader(): Read an MP3 file with a .mp3 file extension.

  This function will load the specified MP3 file into memory using the tuneR package. This is useful for working with music files as a data set.

• mtp.reader(): Read a Minitab Portable Worksheet with a .mtp3 file extension.

• octave.reader(): Read an Octave file with a .m file extension.

  This function will load the specified Octave file into memory using the foreign::read.octave function.

• ppm.reader(): Read a PPM file with a .ppm file extension.

  Data is loaded using the pixmap::read.pnm function.

• r.reader(): Read an R source file with a .R file extension.

  This function will call source on the specified R file, executing the code inside of it as a way of generating data sets dynamically, as in many Monte Carlo applications.

• rdata.reader(): Read an RData file with a .rdata or .rda file extension.

  This function will load the specified RData file into memory using the load function. This may generate many data sets simultaneously.

• rds.reader(): Read the RDS file format from files with the .rds extension.

• spss.reader(): Read an SPSS file with a .sav file extension.

  This function will load the specified SPSS file into memory. It will convert the resulting list object into a data frame before inserting the data set into the global environment.

• sql.reader(): Read a database described in a .sql file.

• stata.reader(): Read a Stata file with a .stata file extension.

• systat.reader(): Read a Systat file with a .sys or .syd file extension.

• tsv.reader(): Read a tab separated values file with the .tsv or .tab file extensions.

• url.reader(): Read a remote file described in a .url file.

  This function will load data from a remote source accessible through HTTP or FTP based on configuration information found in the specified .url file. The .url file must specify the URL of the remote data source and the type of data that is available remotely. Only one data source per .url file is supported currently.

  Examples of the DCF format and settings used in a .url file are shown below:

  Example 1 url: http://www.johnmyleswhite.com/ProjectTemplate/sample_data.csv separator: ,

• wsv.reader(): Read a whitespace separated values file with the .wsv or .txt file extensions.

• xls.reader(): Read an Excel file with a .xls file extension.

  This function will load the specified Excel file into memory using the readxl package.

• xlsx.reader(): Read an Excel 2007 file with a .xlsx file extension.

  This function will load the specified Excel file into memory using the readxl package.

• xport.reader(): Read an XPort file with a .xport file extension.

See Also

.add.extension

johnmyleswhite/ProjectTemplate documentation built on April 24, 2024, 9:23 a.m.