Quote of stock price in R

Inspired by How to Download Historical Stock Data into Matlab.

As an example, suppose you want to query the date of the google stock start from 06-01-2009 to 03-06-2010. Simply replace the string after

• s = with "GOOG", the symbol of google
• a = start month minus one
• b = start day
• c = start year
• d = until month minus one
• e = until day
• f = until year

The resultant query URL will look like below:

http://ichart.finance.yahoo.com/table.csv?s=GOOG&a=05&b=01&c=2009&d=02&e=06&f=2010&g=d&ignore=.csv

The R code is attached below:

# TODO: Query Stock Date
# 
# Author: Everett Roger Qin
###############################################################################
rm(list = ls(all = TRUE))

#set the working directory
setwd('Your working directory')

###############################################################################
# symbol-the symbol of the stock
# fromDate, Date Class of the starting date of the query
# untilDate, Date Class of the ending date of the query
###############################################################################
stockURL <- function(symbol,fromDate, untilDate)
{
 # parse the input Date to day/month/year
 fromDate <- as.Date(fromDate)
 untilDate <- as.Date(untilDate)
 from_day <- as.integer(format(fromDate,"%d"))
 # a= the start month (minus 1)
 from_month <- as.integer(format(fromDate,"%m"))- 1
 from_year <- as.integer(format(fromDate,'%Y'))
 until_day <- as.integer(format(untilDate,"%d"))
 until_month <- as.integer(format(untilDate,"%m")) - 1
 until_year <- as.integer(format(untilDate,'%Y'))
 
 queryURL <- sprintf('http://ichart.finance.yahoo.com/table.csv?s=%s&a=%d&b=%d&c=%d&d=%d&e=%d&f=%d&g=d&ignore=.csv',
   symbol,from_month,from_day,from_year, until_month,until_day,until_year)
 return(queryURL)
 
}
data <- read.csv(stockURL('CFW','2010-02-05',Sys.Date()),header = TRUE)