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charles mills
1,856 PointsCan someone give me a somewhat detailed explanation of the code here
import random
def random_item(argument): index = random.randint(1, len(argument)-1) return argument[index]
index = random.randint(1, len(argument)-1) # I understand that we have a random integer being generated, I don't understand that len gives the length of the argument I don't understand the "1," and i do not undestand the -1 I fail to see how that could give the 4th letter. Is the -1 decrementing anything?
2 Answers
Guy Scorpion
11,053 PointsI think what is tripping you up is len() starts a count from 1 and index starts a count from 0.
len() returns the length of an object.
For example: len('item') would return 4 because there are 4 letters in the string "item".
When you are working with an index the count starts from 0. So the first letter is going to be position 0 not position 1.
Example:
argument = 'item'
argument[0]
# would be equal to "i".
# i is the first letter in the string 'item' so it is index position 0
argument[3]
# would be equal to "m".
# m is the fourth letter in the string 'item' so it is index position 3.
random.randint(1, len(argument)-1)
randint will generate a random integer within a range you set. In this case it is a random integer between 1 and the length of 'argument' - 1.
So if argument was the string "item" it would generate a random integer between 1 and 3 (number of letters in "item" = 4, therefore 4 - 1 = 3). Since your function needs to return an index of 'argument' you need need to do len()-1 because index starts from 0 not 1.
argument = 'item'
argument[4]
# even though there are 4 letters in 'item' this would return an error because there is no index 4.
# The last letter in this example is [3]
charles mills
1,856 PointsThanks, this makes sense. I see the point of the exercise now.