Casey Novak Exercise #7 Answers

Tutorial9_Answers.R

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+# Tutorial 9, Exercise 7
+
+# Problem 1
+
+#Set working directory 
+setwd("~/Desktop/Fall-2021/Biocomputing/Tutorial9/Biocomp_tutorial9")
+#Define a variable with the file to return lines from 
+exampleFile <- read.table("iris.csv",header=TRUE,sep=",")
+#Define variable representing the number of lines to be returned from the top of the file (can be any number)
+numLines = 8
+#Select certain number of lines from the top of the file (use square bracket indexing)
+results <- exampleFile[1:numLines, ]
+#Print file content to terminal 
+results
+
+# Problem 2
+
+# Load data from 'iris.csv'
+irisFile <- read.table("iris.csv",header=TRUE,sep=",")
+# Print the last two rows in the last two columns to the R terminal  
+irisFile[149:150,4:5]
+# Get the number of observations for each species in the data set 
+sum(irisFile$Species=='setosa')
+sum(irisFile$Species=='versicolor')
+sum(irisFile$Species=='virginica') 
+# Get rows with Sepal.Width > 3.5 
+irisFile[irisFile$Sepal.Width>3.5,]
+# Write the data for the species setosa to a comma-delimited file named 'setosa.csv'
+setosaData<-irisFile[irisFile$Species=='setosa',]
+write.csv(setosaData,file = 'setosa.csv',row.names=FALSE)
+# Calculate the mean, minimum, and maximum of Petal.Length for observations from virginica
+mean(irisFile$Petal.Length[irisFile$Species=='virginica'])
+min(irisFile$Petal.Length[irisFile$Species=='virginica'])
+max(irisFile$Petal.Length[irisFile$Species=='virginica']) 
+