NAME

Finance::Shares::Sample - Price data on a single share

SYNOPSIS

    use Finance::Shares::Simple;

Simplest

Obtain a series of stock quotes from a CSV file.

    my $ss = new Finance::Shares::Sample(
                source  => 'gsk,csv',
                symbol  => 'GSK.L',
            );

Typical

Get a series of stock quotes and graph them using specific settings. Calculate some trend lines from the Finance::Shares::Sample data and superimpose them on the graph.

    my $s = new Finance::Shares::Sample(
            source => {
                user     => 'guest',
                password => 'a94Hq',
                database => 'London',
            },
            
            dates_by   => 'weeks',
            symbol     => 'GSK.L',
            start_date => '2001-09-01',
            end_date   => '2002-08-31'
        );

    # construct data for lines, and then...
    $s->add_line( 'prices', 'one', $line1, 'Support' );
    $s->add_line( 'volumes', 'two', 'Average' );
    $s->add_line( 'cycles', 'three', $line3, 'RSI' );

DESCRIPTION

This module is principally a data structure holding stock quotes. Price and volume data are held for a particular share over a specified period. This data can be read from a CSV file or from an array, but more usually it is fetched from Finance::Shares::MySQL which in turn handles getting the data from the internet.

The Data

This object is used as a data structure common to a number of modules. Therefore, unusually, most of the internal data is made available directly. Those documented here can be relied upon to exist as soon as the object has been constructed.

open, high, low, close, volume

These hashes are indexed by date and return the appropriate value for that date. The volume hash is not used when dates_by is set to months.

lx

This hash, indexed by date, returns the logical x coordinate for that date.

dates

This array is a list of known dates indexed by the logical x coordinate. It is the inverse to lx, where

    $x    = $s->{lx}{$date};
    $date = $s->{dates}[$x];

lines

Function data is stored in this hash, first keyed by the chart where the function belongs - one of prices, volumes, cycles or signals. Each of these are in turn sub-hashes keyed by a line id. See <add_line> for details of the data stored.

Example

A function line with two points on the prices graph would be entered thus.

    my $s = new Finance::Shares::Sample(...);
    
    my $data = { 
        '2002-01-11' => 850,
        '2002-03-28' => 991,
    };
    $s->add_line('prices', 'my_trend', $data, 'My Trend');

It would be held within the Sample object thus.

    $s->{lines}{prices}{my_trend}{data}{2002-01-11} = 850;
                                       {2002-03-28} = 991;

CONSTRUCTOR

new( [options] )

options can be a hash ref or a list of hash keys and values.

source and symbol must be specified, with start_date and end_date also required if the source is a mysql database.

Recognized keys are:

source

This can be a Finances::Shares::MySQL object or a hash ref holding options suitable for creating one. Alternatively it may be the name of a CSV file or an array ref holding similar data.

Example 1

Using an existing MySQL object.

    my $db = new Finance::Shares::MySQL;            
    my $ss = new Finance::Shares::Sample (
                source => $db,
            );

Example 2

Creating our own MySQL connection.

    my $ss = new Finance::Shares::Sample (
                source => {
                    user     => 'wally',
                    password => '123jiM',
                    database => 'London',
                },
            );

Several attempts (see tries below) are made to fetch the data from the internet. Then the data is extracted from the MySQL database, filtered according to dates_by and stored as date, price and volume data.

The CSV file is read and converted to price and/or volume data, as appropriate. Files downloaded from !Yahoo Finance need filtering to change the dates into the YYYY-MM-DD format. Alternatively, a script, fetch_csv is provided in the Finance::Shares directory. The comma seperated values are interpreted by Text::CSV_XS and so are currently unable to tolerate white space. See the array option for how the field contents are handled. Optionally, the directory may be specified seperately.

Example 3

    my $ss = new Finance::Shares::Sample (
                source => 'quotes.csv',
                directory => '~/shares',
            );

If source is an array ref it should point to a list of arrays with fields date, open, high, low, close and volume.

Example 4

    my $data = [
    ['2002-08-01',645.13,645.13,586.00,606.36,33606236],
    ['2002-08-02',574.75,620.88,558.00,573.00,59618288],
    ['2002-08-05',589.88,589.88,560.11,572.42,20300730],
    ['2002-08-06',571.89,599.00,545.30,585.92,26890880],
    ['2002-08-07',565.11,611.00,560.11,567.11,24977940] ];
    
    my $ss = new Finance::Shares::Sample ( 
                source => $data,
            );

Three formats are recognized:

    Date, Open, High, Low, Close, Volume
    Date, Open, High, Low, Close
    Date, Volume

Examples

    [2001-04-26,345,400,300,321,12345678],
    [2001-04-27,234.56,240.00,230.00,239.99],
    [2001-04-28, 987654],

The four price values are typically decimals and the volume is usually an integer in the millions.

dates_by

Control how the data are stored. Suitable values are 'days', 'weeks' or 'months'. For weeks or months the average price and volume data is given under the last known day. (Default: 'days')

end_date

The last day of price data, in YYYY-MM-DD format. Only used if the data is fetched using Finance::Shares::MySQL. See fetch.

symbol

The market abbreviation for the stock as used by Yahoo. Non-US codes should have a suffix indicating the stock exchange (e.g. BSY.L for BSkyB on the London Stock Exchange).

mode

Determines how the stock quotes are obtained if Finance::Shares::MySQL is used. Suitable values are 'online', 'offline' and 'cache'. (Default: 'cache')

start_date

The first day of price data, in YYYY-MM-DD format. Only used if the data is fetched using Finance::Shares::MySQL. See fetch.

add_line( graph, lineid, data, key [, style [, shown ]] )

graph: The graph where the line should appear, one of 'prices', 'volumes', 'cycles' or 'signals'.
lineid: A string uniquely identifying the line.
data: A hash ref of values indexed by date.
key: The text to be shown next with the style in the Price Key box to the right of the chart.
style: This can either be a PostScript::Graph::Style object or a hash ref holding options for one.
shown: True if to be drawn, false otherwise.

Add a line to the price chart to be drawn in the style specified identified by some key text. The data is stored as a hash with the following keys:

    data    A hash of numbers keyed by YYYY-MM-DD dates.
    shown   True if the line is to be drawn on a chart.
    style   A hash or PostScript::Graph::Style object.
    key     A string associated with the style in the Key.

Example

    my $s = new Finance::Shares::Sample(...);
    $s->add_line('cycles', 'my_line', $data, 'My Line');

then

    $s->{lines}{cycles}{my_line}{key} == 'My Line';

value( options )

Produce a comparison line for a fixed y value.

options are in key/value format using the following keys.

strict: If 1, return undef if the average period is incomplete. If 0, return the best value so far. (Default: 0)
shown: A flag controlling whether the function is graphed. 0 to not show it, 1 to add the line to the named graph. (Default: 1)
graph: A string indicating the graph for display: one of prices, volumes, cycles or signals. (Default: 'prices')
value: The Y value indicating the line.

Like all function methods, this returns the line identifier.

ACCESS METHODS

See DESCRIPTION for the data items that are directly available.

id()

Return a string used to identify the sample.

start_date()

Returns date of first quote in YYYY-MM-DD format.

symbol()

Returns the !Yahoo stock code as given to new().

end_date()

Returns date of last quote in YYYY-MM0DD format.

dates_by()

Return a string indicating how the dates are spread. One of 'data', 'days', 'workdays', 'weeks', 'months'.

known_lines( [ graph(s) ] )

Returns a list of line identifiers valid for the specified graphs, zero or more of prices, volumes, cycles or signals. If none are specified, all known lines are returned.

choose_line( graph, line [, original ] )

Return the data for the identified line. The data may be checked and any missing values interpolated.

graph: One of prices, volumes, cycles or signals.
line: A string identifying the line.
original: If true, the original (not interpolated) line is returned.

Returns undef if there is no such line. choose_line therefore indicates whether the line exists or not (best called with original=1 for this).

DATE FUNCTIONS

There are three types of dates here. A 'days' value is the number of days from some arbitrary day zero. A 'date' is a string in YYYY-MM-DD format while 'ymd' refers to an array holding a year, month and day such as (2002, 12, 31). See SYNOPSIS for all the functions.

today_as_string

Return today's date in YYYY-MM-DD format.

string_from_ymd( year, month, day )

Convert the numeric representation of year, month and day into a YYYY-MM-DD date.

ymd_from_string( date )

Convert a YYYY-MM-DD date into an array of numeric values in the form:

    (year, month, day)

increment_days( year, month, day, inc_days )

Add inc_days to the date and return as a year-month-day array.

increment_date( date, days )

Add the number of days given to the YYYY-MM-DD date and return the new date in YYYY-MM-DD format.

days_difference( year1, month1, day1, year2, month2, day2 )

Return the number of days between the two dates

day_of_week( year, month, day )

Returns 1=Monday, ... 7=Sunday.

BUGS

Please report those you find to the author.

AUTHOR

Chris Willmot, chris@willmot.org.uk

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