Luck R code for exercise 7

Exercise7Rcode.R

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+### Exercise 7 - Early Days of R
+
+## Problem 1
+## Write R code that replicates the functionality of the head function
+
+# define variable using data file
+allLines<-read.table("file",header=TRUE,sep=",",stringsAsFactors=FALSE)
+# define variable for number of lines to be returned from top of data file
+returnLines<-allLines[1:n,]
+# Testing my code: Returning first 8 lines from wages.csv
+allLines<-read.table("wages.csv",header=TRUE,sep=",",stringsAsFactors=FALSE)
+returnLines<-allLines[1:8,]
+returnLines
+
+## Problem 2
+## Load data from iris.csv and write R code to complete the five following tasks:
+iris<-read.table("iris.csv",header=TRUE,sep=",",stringsAsFactors=FALSE)
+
+# Print the last 2 rows in the last to columns
+dim(iris)
+iris[149:150,4:5]
+
+# Get the number of observations for each species in the data set
+orderedSpecies<-iris[order(iris$Species, decreasing=TRUE),]
+sum(orderedSpecies$Species=="virginica")
+sum(orderedSpecies$Species=="versicolor")
+sum(orderedSpecies$Species=="setosa")
+
+# Get rows with Sepal.Width > 3.5
+sepalWidth<-iris[,2]
+iris[sepalWidth>3.5,]
+
+# Write the data for setosa to a comma-delimited file 'setosa.csv'
+species<-iris[,5]
+setosa<-iris[species=="setosa",]
+write.table(x=setosa,file="setosa.csv",row.names=FALSE,col.names=TRUE,sep=",")  
+
+# Calc mean, min, and max of Petal.Length for observations in virginica
+virginica<-iris[species=="virginica",]
+virginicaPetalLength<-virginica[,3]
+mean(virginicaPetalLength)
+min(virginicaPetalLength)
+max(virginicaPetalLength)