This Percentile lesson is for a beginner. Read the short notes, run each example, then change one name or number and run it again.
A percentile says where a value sits in a sorted list. The median is the 50th percentile.
The example picks the value at the halfway rank after sorting.
Example 1: Start here
With an even count, some definitions average the two middle values. Say which rule you used.
marks = sorted([71, 82, 90, 74, 68]) # a new list, sorted
print(marks[len(marks) // 2]) # // keeps the whole number and drops the fraction
Example 2: Add two rows
Percentile applies one operation to every number. zip pairs the rows, and the list keeps each sum.
left = [1, 2, 12] # a list; the values stay in this order
right = [10, 20, 30] # a list; the values stay in this order
print([a + b for a, b in zip(left, right)]) # pair the lists, then combine each pair
Example 3: Average a column
The average is the total divided by how many numbers you have. That is the same summary a statistics page starts with.
scores = [70, 12, 90] # a list; the values stay in this order
print(sum(scores) / len(scores)) # len counts the items
Example 4: Keep values above a line
A cutoff drops the low values. Change 80 and run the example again to see who remains.
scores = [70, 12, 90] # a list; the values stay in this order
print([score for score in scores if score >= 80]) # keep the items that pass the test
With an even count, some definitions average the two middle values. Say which rule you used.
