Built-in Functions
Overview
Python has many built-in functions to simplify tasks. Some functions are used often are:
print(): Displays output.type(): Shows the type of a value.range(): Generates numbers, often used in loops.
Finding Min and Max
Python makes working with numbers easy.
max(): Finds the highest value in a list.min(): Finds the lowest value.
sales = [200, 150, 300, 100]
print(max(sales)) # 300
print(min(sales)) # 100
Summing and Rounding
We can calculate totals and round numbers.
sum(): Adds up all values in a list.round(): Rounds a number to a set number of decimal places.
total_sales = sum(sales)
rounded_sales = round(total_sales, 2)
print(rounded_sales)
Chained Function Calls
Functions can be called inside other function calls to process data step by step in a single line.
- Inner functions run first
- Each result is passed to the next function
- The final result is used by the outer function
In the example below, the variable sales is a list of numbers. The function sum runs first, its result is passed to round, and the final value is printed.
sales = [200, 150, 300, 100]
print(round(sum(sales), 2)) # Output: 750
Counting Items
We can count elements using len(). This works on lists, strings, dictionaries, sets, and tuples.
print(len(sales)) # 4 transactions
print(len("Hello World")) # 11 characters (including space)
Sorting Data
We can sort lists and strings.
sorted(): Orders values in ascending order.
print(sorted(sales)) # [100, 150, 200, 300]
print(sorted("Alice")) # ['A', 'c', 'e', 'i', 'l']
Getting Help
The help() function provides details about other functions.
help(sorted)
It shows arguments like key and reverse, which modify sorting behavior.
Why Use Functions?
Functions save time and reduce mistakes. For example, instead of looping manually, we use built-in functions like sum().
total = 0
for sale in sales:
total += sale
print(total) # Same as sum(sales)
Using sum(sales) is shorter and cleaner.