Session 3 (2.1): Trying Functions

###### Problem 1 starts here
print("Problem 1")
# myLength() function

myLength <- function(a)
{
  length(a)
}

test_vector1 = c(7, 8, 9, 10, 11, 12, 100)

y1 = myLength(test_vector1)
print(y1) #should return 7 for test_vector1, is what occurs.

# Be sure to test it with vectors of known length!

######## Problem 2 starts here ######
print("Problem 2")

# myMean() function

myMean <- function(b)
{
  sum = 0
  for (value in b)
  {sum = sum + value}
  average = sum / length(b)
}

test_vector2 = c(70, 80, 9, 10, 11, 12, 100)

y2 = myMean(test_vector2)
print(y2)

######## Problem 3 starts here ######
print("Problem 3")


# The following is test code for me to test your myMean function.
# You can comment it out while you're writing your code, but make sure you
# leave it intact in your final submission.
# This should output the correct mean of TestDataSet.
TestDataSet <- c(200, 3.5, 4.00567, 82, 0, 900, 3.14159, 2.72)

myVariance = function(vector)
{
  n = length(vector) 
  mean = myMean(vector) 
  index = 1:n
  sum = 0
  
  for(position in index) #changed from index in vector
  {
    y = (vector[position] - mean)^2 #may need to iterate over this
    sum = sum + y
  }
  
  variance = (sum) / (n-1) #changed the square to up above, at y
  return(variance)
}

# Test code for grading
print(myVariance(TestDataSet)) #should print 96879.53



######## Problem 4 starts here ########
print("Problem 4")
# declare your myMin() function here
# make sure you call it "myMin"

myMin <- function(vector) ####ALSO FIND A WAY TO PRINT POSITION OF THE VECTOR####
{
  min = Inf # Needed to pre-define. highest possible value, should be replaced with any value in TestDataSet
  length_of_vector = length(vector)
  
  
  for (n in length_of_vector)
  {
    value = vector[n]
    
    if (value < min) #as we go through this vector, if value is lower than min, set value to the new minimum
    {min = value}
  }
  return(min)
}

TestDataSet = c(55, 999, 10, 2, 3, 1) 


# Test code for grading
print(myMin(TestDataSet)) #should print 0 5

######## Problem 5 starts here ########
print("Problem 5")
# declare your myMax() function here
# make sure you call it "myMax"

myMax <- function(vector) ####Issues with obtaining maximum -- still fetches minimum value.####
{
  max = 0 # Needed to pre-define. lowest possible value, should be replaced with any value in TestDataSet
  length_of_vector = length(vector)
  
  
  for (n in length_of_vector)
  {
    value = vector[n]
    
    if (value > max) #as we go through this vector, if value is lower than min, set value to the new minimum
    {max = value}
  }
  return(max)
}

TestDataSet = c(55, 999, 10, 2, 3, 1)



# Test code for grading
print(myMax(TestDataSet)) #should print 900 6


########## Problem 6 starts here ######
print("Problem 6")
# Declare your mySecondSmallest() function here



# Test code
print(mySecondSmallest(TestDataSet)) #should print 2.72 8


######### Problem 7 starts here ######
print("Problem 7")
# Declare your functions here




TestDataSet_withRepeats <- c(200, 3.5, 4.00567, 82, 0, 900, 3.14159, 2.72,0,0,2.72,4)
print(myMin_withRepeats(TestDataSet_withRepeats)) #should print 0 5 9 10
print(mySecondSmallest_withRepeats(TestDataSet_withRepeats)) #should print 2.72 8 11