Introduction to Python Programming

# 9.3Common list operations

Introduction to Python Programming9.3 Common list operations

## Learning objectives

By the end of this section you should be able to

• Use built-in functions max(), min(), and sum().
• Demonstrate how to copy a list.

## Using built-in operations

The max() function called on a list returns the largest element in the list. The min() function called on a list returns the smallest element in the list. The max() and min() functions work for lists as long as elements within the list are comparable.

The sum() function called on a list of numbers returns the sum of all elements in the list.

## Example 9.3

### Common list operations

    """Common list operations."""

# Set up a list of number
snum_list = [28, 92, 17, 3, -5, 999, 1]

# Set up a list of words
city_list = ["New York", "Missoula", "Chicago", "Bozeman",
"Birmingham", "Austin", "Sacramento"]

# Usage of the max() funtion
print(max(num_list))

# max() function works for strings as well
print(max(city_list))

# Usage of the min() funtion which also works for strings
print(min(num_list))

print(min(city_list))

# sum() only works for a list of numbers
print(sum(num_list))


The above code's output is:

    999
Sacramento
-5
Austin
1135


## Concepts in Practice

### List operations

1.
What is the correct way to get the minimum of a list named nums_list?
1. min(nums_list)
2. nums_list.min()
3. minimum(nums_list)
2.
What is the minimum of the following list?
["Lollapalooza", "Coachella", "Newport Jazz festival", "Hardly Strictly Bluegrass", "Austin City Limits"]
1. Coachella
2. Austin City Limits
3. The minimum doesn't exist.
3.
What value does the function call return?
sum([1.2, 2.1, 3.2, 5.9])
1. sum() only works for integers.
2. 11
3. 12.4

## Copying a list

The copy() method is used to create a copy of a list.

## Concepts in Practice

### Copying a list

4.
What is the output of the following code?
my_list = [1, 2, 3]
list2 = my_list
list2[0] = 13
print(sum(my_list))
1. 6
2. 13
3. 18
5.
What is the output of the following code?
my_list = [1, 2, 3]
list2 = my_list.copy()
list2[0] = 13
print(max(my_list))
1. 3
2. 13
3. 18
6.
What is the output of the following code?
my_list = ["Cat", "Dog", "Hamster"]
list2 = my_list
list2[2] = "Pigeon"
print(sum(my_list))
1. CatDogPigeon
2. Error

## Try It

### Copy

Make a copy of word_list called wisdom. Sort the list called wisdom. Create a sentence using the words in each list and print those sentences (no need to add periods at the end of the sentences).

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