learnpython.ipynb

Kernel: Python 2

Jupyter Task 3

Sidy Danioko

Sean Paradiso

Python Syntax

- Comments in python are anything preceeded by a '#'

# This is a comment 

- Declaring a variable does not require a type

a = 5 
myName = "Sean"

- The syntax for printing output is print("string1" + "string2")

a = 5
print a
print myName

5
Sean

Python Data Types

- The boolean data type is a binary taking True and/or False

a = 2
b = 2

if False:
    print "They are the same"
    
else:
    print "They are different"

They are different

- The integer data type is a primitive data type used for integers

a = 3
type(a)

int

- The float data type is a primitive data type used for real numbers

a = 6.3
b = 2.6

c = a / b

print(c)

type(c)

2.42307692308

float

- The string data type is a primitive data type used for an array of characters

myName = "Sean Paradiso"

print(myName)

type(myName)

Sean Paradiso

str

- The list data type is a primitive data type used for a collection of items of the same or different types in a specific order

u = range(0,10)

print(u)

type(u)
print u[0]
print u[1]
u[2]= 100
print u[2]
print u

type(u)

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
0
1
100
[0, 1, 100, 3, 4, 5, 6, 7, 8, 9]

list

- The tuple data type is an immutable ordered list

myTup = (1,2,3,4,5,6,7,8)

print myTup
type(myTup)

myTup(0) = 30 #We cannot change values within the tuple

  File "<ipython-input-32-6ef0b3d75e39>", line 6
    myTup(0) = 30
SyntaxError: can't assign to function call

- The dictionary data type is a key-value system

FamilyAge = {"Mom": 100, "Dad": 90, "Brother": 50}

print(FamilyAge)

for item in FamilyAge:
    print item
    
for value in FamilyAge:
    print FamilyAge[value]
    
type(FamilyAge)

{'Dad': 90, 'Brother': 50, 'Mom': 100}
Dad
Brother
Mom
90
50
100

dict

- The set data type is similar to a list with the exception of not allowing duplicates

mySet = set([1, 2, 3, 3, 3, 4, 5])

print(mySet)
type(mySet)

#Let's add some items to mySet

mySet.add(8)
mySet.add("You the man")

print(mySet)

type(mySet)

set([1, 2, 3, 4, 5])
set([1, 2, 3, 4, 5, 8, 'You the man'])

set

Python Control Structures

- The syntax for an if-then-else control structure is used by initiating with the key word "if" followed by a test

a = input("Please enter an integer: ")
if(a%2==0):
    print " a is an even number"
else:
    print " a is an odd number"

first = raw_input("Please enter your first name :")

if(len(first) > 4):
    print " Your name is too long"
else:
    print " Your name is short"

Please enter an integer: 5
 a is an odd number
Please enter your first name :sdivhjsldivilsdj
 Your name is too long

- The syntax for a for loop control structure is used by initiating with the key word "for" which will iterrate through a list. (This means the final value within the given range is the stopping condition and will not be evaluated)

#This for loop prints the squares of the values within the specified range

for i in range(1,10):
    print i**2

1
4
9
16
25
36
49
64
81

- The syntax for a for while control structure is used by initiating with the key word "while" which will iterrate through a list until a condition is no longer met. (This means the final value within the given range is the stopping condition and will not be evaluated)

while True:
    name = raw_input("Please a give me a name or type x to exit: ")
    if name == "x":break
    else:
        print "Keep going"

Please a give me a name or type x to exit: 5
Keep going
Please a give me a name or type x to exit: x

Python Organizational Structures

- The syntax for defining a function with a name as an organizational structure creates a new function through the use of the key word "def" and returns a value with a return statement

def sub(x, y):
    print "x is {0} and y is {1}".format(x, y)
    return x - y

sub(12, 4)

x is 12 and y is 4

8

- The syntax for including a docstring is an indented block surrounded by quotes

def sub(x, y):
    "Return the difference of user define x and y" #<- the preceding is a docstring
    print "x is {0} and y is {1}".format(x, y)
    return x - y

sub(12, 4)

x is 12 and y is 4

8

- The syntax for *args is a list in which superfluous arguments are placed

def PlayAround(a,b,c):
    return a+b*c

mytuple=(2,3,5)
PlayAround(*mytuple)

def mylist(*food):
    print food
    
mylist('apples')
mylist('apples','chicke','rice')
    

('apples',)
('apples', 'chicke', 'rice')

- The syntax for **kwargs is taking additional arguments and places them in a dictionary with a title of your choosing. This title can be anything as long as it is preceeded by two asterisks (in this example we have **kwargs)

def myfamily(**kwargs):
    for name, age in kwargs.items():
        print '{0} is {1} years old'.format(name, age)

myfamily(Dad = 100, Mom = 90)

def print_table(**kwargs):
    for key, values in kwargs.items():
        print(key,values)
        
print_table(a= 10,b = -3, c = 100)

Dad is 100 years old
Mom is 90 years old
('a', 10)
('c', 100)
('b', -3)