Coursera : Getting and Cleaning Data - Week 1 Quiz

Masa nak buat quiz 1

Question 3

Download the Excel spreadsheet on Natural Gas Aquisition Program here:

• https://d396qusza40orc.cloudfront.net/getdata%2Fdata%2FDATA.gov_NGAP.xlsx

Read rows 18-23 and columns 7-15 into R and assign the result to a variable called dat

What is the value of sum(dat$Zip*dat$Ext,na.rm=T)?

Dapat error message berikut:

R is giving you an error -- could not find function

lepas tu x boleh load package xlsx , sangkut lak rjava 

library(rJava)
Error in get(Info[i, 1], envir = env) : 
  lazy-load database 'C:/Users/sony/Documents/R/win-library/3.1/rJava/R/rJava.rdb' is corrupt
In addition: Warning message:
In get(Info[i, 1], envir = env) : internal error -3 in R_decompress1
Error: package or namespace load failed for ‘rJava’

Penyelesaian:

Step 1:

Note that it is necessary to ‘manually download and install’ the 64 bit version of JAVA. By default, the download page gives a 32 bit version .

You can pick the exact version of Java you wish to install from this link. If you might (for some reason) work on both versions of R, you can install both version of Java (Installing the “Java Runtime Environment” is probably good enough for your needs).
(Source: Uwe Ligges)

Step 2:

This will call up this dialog box with edit rights for the PATH variable (and other system variables):

Step 4:

Dalam R

  Sys.setenv(JAVA_HOME="")

Installing and loading xlsx package

• Install

install.packages("xlsx")

• Load

library("xlsx")