Coursera Computing in Data Analysis Assignment 1 Part 1 Week 2

Write a function named 'getmonitor' that takes THREE (3) arguments:
(1) 'id'
(2) 'directory'
(3) 'summarize'

Given a monitor ID number, 'getmonitor' reads that monitor's particulate matter data from the directory specified in the
'directory' argument and returns a data frame containing that monitor's data. If 'summarize = TRUE', then 'getmonitor' produces
a summary of the data frame with the 'summary' function and prints it to the console.

Please save your code to a file named getmonitor.R. To run the test script for this part, make sure your working directory has
the file getmonitor.R in it and the run:

source(“http://spark-public.s3.amazonaws.com/compdata/scripts/getmonitor-test.R”)
getmonitor.testscript()

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# | I N I T I A L I Z A T I O N |
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Init <- function(workDirStr = "C:/Users/denbrige/100 FxOption/103 FxOptionVerBack/080 Fx Git/R-source") {
    setwd(workDirStr)
}

#
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# | I N T E R N A L F U N C T I O N S |
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getmonitor <- function(id, directory, summarize = FALSE) {
    # --- Assert 'id' is a vector of length 1 indicating the monitor ID
    # number. The user can specify 'id' as either an integer, a character, or
    # a numeric.  'directory' is a character vector of length 1 indicating the
    # location of the CSV files 'summarize' is a logical indicating whether a
    # summary of the data should be printed to the console; the default is
    # FALSE

    # --- Assert construct file name Directory is pre-appended to file name.
    # Use sprintf() to add leading zeroes.  E.g. 'specdata/001.csv'
    fileStr <- paste(directory, "/", sprintf("%03d", as.numeric(id)), ".csv", 
        sep = "")

    # --- Assert read csv
    rawDfr <- read.csv(fileStr)

    # --- Assert summary if true
    if (summarize) {
        print(summary(rawDfr))
    }

    # --- Return value is a data frame
    return(rawDfr)
}

#
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# | M A I N P R O C E D U R E |
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# --- Init set working directory
Init()

# --- Get data frame as ID = 1
data <- getmonitor(1, "specdata")
head(data)

##         Date sulfate nitrate ID
## 1 2003-01-01      NA      NA  1
## 2 2003-01-02      NA      NA  1
## 3 2003-01-03      NA      NA  1
## 4 2003-01-04      NA      NA  1
## 5 2003-01-05      NA      NA  1
## 6 2003-01-06      NA      NA  1

# --- Get data frame and summary as ID = 101
data <- getmonitor(101, "specdata", TRUE)

##          Date        sulfate        nitrate           ID     
##  2005-01-01:  1   Min.   : 1.7   Min.   : 0.2   Min.   :101  
##  2005-01-02:  1   1st Qu.: 3.1   1st Qu.: 0.6   1st Qu.:101  
##  2005-01-03:  1   Median : 4.3   Median : 1.1   Median :101  
##  2005-01-04:  1   Mean   : 6.3   Mean   : 2.3   Mean   :101  
##  2005-01-05:  1   3rd Qu.: 7.4   3rd Qu.: 2.8   3rd Qu.:101  
##  2005-01-06:  1   Max.   :22.1   Max.   :10.8   Max.   :101  
##  (Other)   :724   NA's   :666    NA's   :666

head(data)

##         Date sulfate nitrate  ID
## 1 2005-01-01      NA      NA 101
## 2 2005-01-02      NA      NA 101
## 3 2005-01-03      NA      NA 101
## 4 2005-01-04      NA      NA 101
## 5 2005-01-05      NA      NA 101
## 6 2005-01-06      NA      NA 101

# --- Get data frame and summary as ID = 200
data <- getmonitor(200, "specdata", TRUE)

##          Date         sulfate        nitrate           ID     
##  2001-01-01:   1   Min.   : 1     Min.   : 0     Min.   :200  
##  2001-01-02:   1   1st Qu.: 2     1st Qu.: 1     1st Qu.:200  
##  2001-01-03:   1   Median : 3     Median : 1     Median :200  
##  2001-01-04:   1   Mean   : 4     Mean   : 2     Mean   :200  
##  2001-01-05:   1   3rd Qu.: 5     3rd Qu.: 3     3rd Qu.:200  
##  2001-01-06:   1   Max.   :23     Max.   :15     Max.   :200  
##  (Other)   :3646   NA's   :3192   NA's   :3188

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