Gain insights into R, the leading language for data analysis. Learn about its basics, advanced concepts, and practical coding to drive valuable insights from large datasets.

The digital world we live in has given companies and people access to staggering amounts of data, and anyone that can make use of that to drive valuable insights stands to benefit. The ability to work with large amounts of data is becoming a standard requirement for countless jobs across multiple industries.

Enter R, probably the most well-known language for data analysis. It's been used for years due to its robust statistical functionality, outstanding graphing ability, and extensibility through packages.

This interactive course will get you up to speed and assumes no prior knowledge of R. You'll start with the very basics and work your way up to advanced concepts like exception handling. By the time you're done, you'll be able to write detailed, useful code in R yourself.

Learn R from Scratch

## Problem Statement
Implement a function `findTopper()` that takes input from three subject files: `math.csv`, `english.csv` and `science.csv`, and find the index of the student that has scored the maximum total marks adding all three of its marks.

### Input
Three files: `math.csv`, `english.csv` and `science.csv`

### Output
Index of the highest scoring student

### Sample Input
`math.csv`
```
Name,   Math
Andrew, 2.5
Mathew, 5.9
Dany,   1.9
Philip, 9.1
```
`english.csv`
```
Name,   English
Andrew, 8.2
Mathew, 2.5
Dany,   7.5
Philip, 9.3
```
`science.csv`
```
Name,   Science
Andrew, 5.2
Mathew, 9.5
Dany,   7.1
Philip, 1.9
```

### Sample Output
```
4
```
### Test Yourself
Write your code in the given area. If you get stuck, you can look at the solution.

Name,   Math
Andrew, 2.5
Mathew, 5.9
Dany,   1.9
Philip, 9.1


Name,   English
Andrew, 8.2
Mathew, 2.5
Dany,   7.5
Philip, 9.3


Name,   Science
Andrew, 5.2
Mathew, 9.5
Dany,   7.1
Philip, 1.9


findTopper <- function() 
{
    # Write your code here
}

findTopper <- function() 
{
    findIndexWithMaxNum <- function(myVector) # helper function that returns the index 
                                        # of the element that has the highest value
    {
        maxNumber = -Inf # We want this to be the lowest possible value for comparison
        maxIndex = 0

        index = 1
        for(i in myVector)
        {
            if(maxNumber < i)
            {
                maxNumber = i # set the max element
                maxIndex = index # set the max element's index
            }
            index = index + 1
        }
        return(maxIndex) # return the index of the max element
    }

    # MAIN FILE HANDLING CODE
    mathData = read.csv("math.csv") # fetch data from math.csv
    englishData = read.csv("english.csv") # fetch data from english.csv
    scienceData = read.csv("science.csv") # fetch data from science.csv

    tempData <- merge(mathData, englishData) # we use the merge function on data frames
    finalData <- merge(tempData, scienceData) # another merge function to merge the remaining data frame

    result <- vector("numeric", 0) # vector to store the total marks of each student

    for(student in 1:length(finalData)) # loop over all the rows/students
    {
        temp <- 0.0 # temporarily stores the total marks of the current student

        for(i in 2:ncol(finalData)){ # loop over all the columns (math, english, science)
        # We iterate from 2 to ncol(finalData) because the 1st column is just names of students

            temp <- temp + as.double(finalData[student, i]) # fetch respective student's marks
        }
        result <- c(result, temp) # store the total marks of the current student
    }
    return(findIndexWithMaxNum(result)) # return the index of the highest scoring student
}

---
In the next lesson, we give a brief overview of the solution to this problem.

# Problem Statement
Implement a function `findTopper()` that takes input from three subject files: `math.csv`, `english.csv` and `science.csv`, and find the index of the student that has scored the maximum total marks adding all three of its marks.

## Input
Three files: `math.csv`, `english.csv` and `science.csv`

## Output
Index of the highest scoring student

## Sample Input
`math.csv`
```
Name,   Math
Andrew, 2.5
Mathew, 5.9
Dany,   1.9
Philip, 9.1
```
`english.csv`
```
Name,   English
Andrew, 8.2
Mathew, 2.5
Dany,   7.5
Philip, 9.3
```
`science.csv`
```
Name,   Science
Andrew, 5.2
Mathew, 9.5
Dany,   7.1
Philip, 1.9
```

## Sample Output
```
4
```
## Test Yourself
Write your code in the given area. If you get stuck, you can look at the solution.

Given multiple subject files find the student who has the maximum total marks.

Getting Started

Variables

Exploring R Objects

R Operators and Notation

Conditional Statements

Loops

Functions

Input/Output

Exception Handling

Classes

Fun Challenges

Conclusion

Challenge 3: Find the Highest Achiever

Problem Statement

Input

Output

Sample Input

Sample Output

Test Yourself