Python.docx

Python can be used on a server to create web applications (server-side)

Single line Comments start with a # """This is a multiline doc string"""

There are three numeric types in Python:   

Int Float: Float can also be scientific numbers with an "e" to indicate the power of 10. complex: x = 3+5j , y = 5j

CASTING: y = int(2.8) # y will be 2 x = float(1)

# x will be 1.0

z = float("3")

# z will be 3.0

z = str(3.0)

# z will be '3.0'

STRING: a = "Hello, World!" print(a[1])

# returns e

print(b[2:5])

# returns llo

print(a.strip()) # returns "Hello, World!" whitespace from the beginning or the end: print(len(a)) print(a.lower()) print(a.upper())

The strip() method removes any

# returns 13 # returns hello, world! # returns

print(a.replace("H", "J"))

HELLO, WORLD! # returns Jello, World!

IF ELSE: a = 200 b = 33 if b > a: m, print("b is greater than a") elif a == b: print("a and b are equal") else: print("a is greater than b") if a > b and c > a: print("Both conditions are True")

if a > b or a > c: print("At least one of the conditions is True") There are four collection(ARRAY) data types in the Python programming language:    

List is a collection which is ordered and changeable. Allows duplicate members. Tuple is a collection which is ordered and unchangeable. Allows duplicate members. Set is a collection which is unordered and unindexed. No duplicate members. Dictionary is a collection which is unordered, changeable and indexed. No duplicate members.

LIST:

A list is a collection which is ordered and changeable. In Python lists are written with square brackets. eg: thislist = ["apple", "banana", "cherry"] Arrays are used to store multiple values in one single variable thislist = ["Ford", "Volvo", "BMW"] x = thislist [0] # returns Ford thislist [0] = "Toyota" # returns ['Toyota', 'Volvo', 'BMW'] thislist.append("Honda") # returns ['Ford', 'Volvo', 'BMW', 'Honda'] thislist.pop(1) # returns ['Ford', 'BMW'] thislist.remove("Volvo") # returns ['Ford', 'BMW'] thislist.insert(1, "Toyota") # returns ['Ford', 'Toyota','BMW']

ARRAY:

Tuple: A tuple is a collection which is ordered and unchangeable (we can’t add or delete value after once it’s initialize). In Python tuples are written with round brackets. thistuple = ("apple", "banana", "cherry") example: thistuple[1] = "blackcurrant" # The values will remain the same: print(thistuple) # returns ('apple', 'banana', 'cherry')

SETS: A set is a collection which is unordered and unindexed. In Python sets are written with curly brackets. You cannot access items in a set by referring to an index, since sets are unordered the items has no index. thisset = {"apple", "banana", "cherry"}

Examples: for x in thisset:

# returns cherry banana apple

print("banana" in thisset)

# Check if "banana" is present in the set: # returns

TRUE

LOOP: Python has two primitive loop commands:  

while loops : With the while loop we can execute a set of statements as

long as a condition is true. for loops : A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string).

i = 1 while i < 6: print(i) if i == 3: break i += 1

# it could be continue or it could neither any of these 2

FOR Loop Through a List

NESTED FOR LOOP:

FOR Loop Through a Tuple thistuple = ("apple", "banana", "cherry") for x in thistuple: print(x)