Course
Data Frames
Convert a List to a DataframeCreate an Empty DataframeCombine Two Dataframe into OneChange Column Name of a DataframeExtract Columns From a DataframeDrop Columns in a DataframeReorder Columns in a DataframeSplit DataframeMerge Multiple DataframesDelete Rows From DataframeMake a List of DataframesIntroduction
"Hello World" ProgramAdd Two VectorsFind Sum, Mean and Product of Vector in R ProgrammingTake Input From UserGenerate Random Number from Standard DistributionsSample from a PopulationFind Minimum and MaximumSort a VectorStrings
Concatenate Two StringsFind the Length of a StringCheck if Characters are Present in a StringExtract n Characters From a StringReplace Characters in a StringCompare two StringsConvert Factors to CharactersTrim Leading and Trailing WhitespacesVectors
Concatenate a Vector of StringsCheck if a Vector Contains the Given ElementCount the Number of Elements in a VectorFind Index of an Element in a VectorAccess Values in a VectorAdd Leading Zeros to VectorR Program to Check if a Number is Positive, Negative or Zero
Example: Check Positive, Negative or Zero
# In this program, we input a number
# check if the number is positive or
# negative or zero and display
# an appropriate message
num = as.double(readline(prompt="Enter a number: "))
if(num > 0) {
print("Positive number")
} else {
if(num == 0) {
print("Zero")
} else {
print("Negative number")
}
}
Output 1
Enter a number: -9.6
[1] "Negative number"
Output 2
Enter a number: 2
[1] "Positive number"
A number is positive if it is greater than zero.
We check this in the expression of if. If it is FALSE, the number will either be zero or negative.
This is also tested in subsequent expression.