Functions

A function is a routine instruction defined by the programmer. They are not associated with objects. Great examples of functions include the built-in functions.

Common Built-In Functions



In [1]:

    
# Length
len([1,2,4])









    Out[1]:





3



In [2]:

    
# Convert to Float
float(2.0)









    Out[2]:





2.0



In [4]:

    
# Covert to int (truncation)
int(3.9)









    Out[4]:





3



In [8]:

    
# Create a Set
set()









    Out[8]:





set()



In [10]:

    
# Bool
bool(2 < 3)









    Out[10]:





True

User-Defined Functions

You can define you rown functions using the def keyword. The syntax is as follows:

def func_name(param1, param2...):
    // code
    // returns if needed

As you would expect, creating your own functions (and later methods) is syntactically painless.



In [11]:

    
# A function that determines if a number is even or odd.

def even_odd(number):
    if number % 2 == 0:
        print("{} is even".format(number))
    else:
        print("{} is odd".format(number))



In [12]:

    
print(even_odd(19))









    



19 is odd
None



In [16]:

    
# A function that sums up a list
summ = 0
def list_sum(lst):
    for item in lst:
        summ += item



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