Assignment: R Programming
Introduction
This assignment relates to a data set containing weather information for Howick (Auckland, New Zealand) from Jan 1 2013 to Jan 9 2013.1
We will start with three files in three different formats, one of which is a CSV format file, BUT you do not know the format of any of the files and the file names do not have informative suffixes. The files are called weather1.a, weather2.b, and weather3.c and are available from the Lesson 1 web site for this course.
Download the three files to a directory on your computer (remember to right-click and "Save link as"; do NOT left-click on the links to the files).
1. Determine which one of the files is the CSV format file using the techniques described in the lecture slides.
2. Write an R expression that calls read.csv() to open the CSV format file from the directory on your computer with R.
The first few lines of the result of your R expression should look like this:
| |
time
|
temp
|
dew
|
hum
|
speed
|
gust
|
dir
|
rain
|
baro
|
|
1
|
00:00
|
14.1
|
11.1
|
82
|
0.0
|
0.0
|
0
|
0
|
1021.0
|
|
2
|
00:10
|
14.2
|
11.4
|
83
|
0.0
|
0.0
|
0
|
0
|
1021.3
|
|
3
|
00:20
|
14.2
|
11.4
|
83
|
0.0
|
0.0
|
0
|
0
|
1021.1
|
|
4
|
00:30
|
13.9
|
11.1
|
83
|
0.0
|
0.0
|
0
|
0
|
1020.9
|
|
5
|
00:40
|
13.7
|
11.0
|
84
|
0.0
|
0.0
|
0
|
0
|
1020.9
|
|
6
|
00:50
|
13.5
|
11.0
|
85
|
0.0
|
1.7
|
205
|
0
|
1020.8
|
3. Write two R expressions that call setwd(), to change R's working directory to be the direc- tory where the file is, then read.csv(), with just the file name, to open the CSV file.
The result should be exactly the same as for the previous question.
For the remainder of the assignment, we will work with nine CSV files called "data20130101.csv" to "data20130109.csv", also are available from the Lesson 1 web site for this course. The first few lines of the first file are shown in Figure 1. Each row of data gives various weather-related values for a time during the day:
• The time (in 10 minute intervals).
• The temperature (degrees Celsius)
• The dewpoint (degrees Celsius)
• The humidity (percentage)
• The average wind speed (km/h)
• The peak wind gust (km/h)
• The average wind direction (degrees)
• The total rainfall (mm)
• The barometer pressure (hPa)
Download the files to a directory on your computer (remember to right-click and "Save link as"; do NOT left-click on the links to the files).
Figure 1: The first few lines of the first file in the weather data set.
4. Write an R expression to open the first file, "data20130101.csv".
The first few lines of the result of your R expression should look like this:
|
time
|
temp
|
dew
|
hum
|
speed
|
gust
|
dir
|
rain
|
baro
|
|
00:00
|
14.1
|
11.1
|
82
|
0.0
|
0.0
|
0
|
0
|
1021.0
|
|
00:10
|
14.2
|
11.4
|
83
|
0.0
|
0.0
|
0
|
0
|
1021.3
|
|
00:20
|
14.2
|
11.4
|
83
|
0.0
|
0.0
|
0
|
0
|
1021.1
|
|
00:30
|
13.9
|
11.1
|
83
|
0.0
|
0.0
|
0
|
0
|
1020.9
|
|
00:40
|
13.7
|
11.0
|
84
|
0.0
|
0.0
|
0
|
0
|
1020.9
|
|
00:50
|
13.5
|
11.0
|
85
|
0.0
|
1.7
|
205
|
0
|
1020.8
|
NOTE: that the result is NOT the same as the result from Assignment 1 (the first column of values is different). In order to get this result, you will need to specify a value of 1 for the row.names argument in your function call to the read.csv() function (to specify that the first column of values in the CSV file should be treated as row names).
5. Write R code to calculate the maximum and minimum values in the first CSV file and assign the results to symbols minValue and maxValue.
You should end up with results that look like this:
> maxValue
[1] 1021.6
> minValue
[1] 0
6. The largest value in the file is a barometer pressure in hectopascals. 1 hectopascal is equiv- alent to 0.0145037738 psi (pounds per square inch). Write R code to convert the maximum value in the file to psi.
You should end up with a result that looks like this:
> maxPSI
[1] 14.81706
7. Write R code to calculate the maximum value across all 9 files. You should end up with a result that looks like this:
> overallMax
[1] 1021.6
Attachment:- CSV-Files.rar