1,576
edits
Changes
m
→PART 3 - Iterating Over Lists
== PART 1 - How User-Defined Functions are Declared and Run ==
:Functions may be designed :* '''not to accept arguments or return a value''', designed * to '''not accept arguments but return a value''', designed * to '''accept arguments and not return a value''', * or designed to '''both accept arguments and return a value'''. In this investigation, will we will focus of on creating functions that either do NOT return a value, or return a value.
'''Functions and Strings'''
</source>The final '''return "ok"''' will only take place if a previous return has not taken place before it. Once return has been used in a function, the function immediately exits and returns the value.
:#Call describe_temperature like this to confirm the results:<source>
print(describe_temperature(50))
# Will return 'hot'
print(describe_temperature(20))
# Will return 'perfect'
print(describe_temperature(-50))
# Will return 'cold'
print(describe_temperature(25))
# Will return 'ok'
print(describe_temperature(10))
# Will return 'ok'
</source>
:#Create a new python file for testing.
:#Import the '''''os''''' module in your python file.
:#You can issue operating system commands by using the '''system()''' function. Try it:<source lang="python">
os.system('ls')
# Notice how the long line below is wrapped to fit on one screen:
print("List length is " + str(length_of_list ) + ", smallest element in the list is " + str(smallest_in_list ) + ", largest element in the list is " + str(largest_in_list))
</source>
print(list_of_numbers)
print(new_list_of_numbers)
</source>The above is just one example of a quick use of for loops mixed with lists. But be careful when passing lists into functions. When you give a function a list as an argument, it is the actual list reference and NOT a copy. This means a function can change the list without making a new list. While you do have to be careful , this can also be useful, a . A function can modify any given list, ''without '' have to return it.<br><br>
:#To demonstrate, run the following code:<source lang="python">
list_of_numbers = [ 1, 5, 2, 6, 8, 5, 10, 2 ]
