Category: Programming

How to send messages using Python

In this tutorial, we will learn to send message using Python. We can use this approach in building new Python applications.

Tools we will be needing :

  1. Python – Version 2 or 3.
  2. Virtual Environment  – To create isolated Python environments
  3. Twilio Trial Account.
  4. Twilio Python helper library.

Twilio API :

We will be using Twilio Python helper library to send messages over the phone. To use Twilio library we will need to create twilio account. Signup for a free account

Twilio Try Twilio Free.png

Once you had signed up on twilio, you will receive verification code on your registered phone number, input this code on twilio verification page and your account is set to use twilio services.

In Trial Mode, Twilio can be only used to send messages to a validated phone number. You will have to upgrade your account in-order to send messages to any phone number.

Now login into twilio and grab twilio account test credentials by click over here.

#Note : Copy your TEST ACCOUNT SID and TEST AUTHTOKEN, we will be using this in python script.

Install Python Dependency

As mentioned earlier that we will be using twilio helper library for our Python application. The library can be install using pip command.

We will start the basic Python Project by first creating virtual environment. Virtual environment are used to isolate different Python environments.

virtualenv sendMsg

Now activate this environment using,

source sendMsg/bin/activate

As we are ready with our virtual environment, go ahead and install twilio library.

pip install twilio

Sending Message from Python Script

Create a new python file i.e sendmsg.py and enter the following code in the file.

# import the Twilio client from the dependency
from twilio.rest import Client

# put your twilio credentials here
account_sid = "{{your_account_sid}}" # get it from https://www.twilio.com/console/phone-numbers/runtime/test-credentials
auth_token = "{{your_authentication_code}}"

client = Client(account_sid, auth_token)

media_url = "https://c1.staticflickr.com/3/2899/14341091933_1e92e62d12_b.jpg"

response = client.messages.create(
    to= "{{enter_your_twillio_account_phone_number}}", #https://www.twilio.com/console/phone-numbers/verified
    from_= "+15005550006", #+15005550006 will be used for trial account.
    body= "Hello, how you doing ?",
    media_url= media_url # if you need to attach multimedia to your message, else remove this parameter.
    )

Now run the python script using

python sendmsg.py

In a few seconds you should be able to see a message appear on your phone – note that messages can sometime take a little longer because we are using test credentials and it might in queued stage. Always check API response to know exact status.

That is everything needed to send messages to phone. Awesome results using few lines of Python code. This code can be added to any Python program to add message sending capabilities.

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Balanced Parentheses Check | Python

Problem : 

Given a string of opening and closing parentheses, 
check whether it’s balanced. 

We have 3 types of parentheses: round brackets: (), square brackets:
[], and curly brackets: {}. 

Assume that the string doesn’t contain 
any other character than these, no spaces words or numbers. 

As a reminder, balanced parentheses require every opening
parenthesis to be closed in the reverse order opened.
For example ‘([])’ is balanced but ‘([)]’ is not.

You can assume the input string has no spaces.

Solution :

def check_balanced_string(s1):
	
	if len(s1)%2 != 0:
		return False

	opening = set('([{')

	matches = set([ ('{','}'), ('[',']'), ('(',')') ])

	stack = []
	for perm in s1:

		if perm in opening:
			stack.append(perm)
		else:

			if len(stack) == 0 :
				return False
			last_val = stack.pop()

			if (last_val,perm) not in matches:
				return False

	return len(stack) == 0

# '([])'
b = check_balanced_string('[()]')
print b

Find the largest continuous sum | Python

Problem :

Given an array of integers(positive and neg),
Find the largest continuous sum .

Solution : 

def large_cont_sum(arr):
	if len(arr) < 1 :
		return 0
	max_sum = current_sum = arr[0]

	for num in arr[1:]:

		current_sum = max(num,current_sum+num)
		max_sum = max(current_sum,max_sum)

	print max_sum

large_cont_sum([1,2,-1,3,4,10,10,-10,-1]) #29

Linked List Nth to Last Node | Python

Problem :

Function that takes a head node and an integer value n and 
then returns the nth to last node in the linked list.

Solution : 

class Node:

    def __init__(self, value):
        self.value = value
        self.nextnode  = None

    def nth_to_last_node(n, head):

	node = head

	nodes = []
	while node != None:
		nodes.append(node)
		node = node.nextnode

	return nodes[-n]

Binary Search | Python

Binary Search implementation in Python

def binary_search(arr,ele):
	"""
		binary_search works only on sorted array, also it follows divide and conquer fundamentals
	"""

	first = 0
	last = len(arr) - 1 # as indexing starts at 0
	found = False

	while first <= last and not found:

		mid = (first+last)/2 # to get mid point of array

		if arr[mid] == ele:
			found = True
		else:
			if ele < arr[mid]:
				last = mid - 1
			else:
				first = mid + 1

	return found

b = binary_search([1,2,3,4,5],2)
print b

Reverse Linked List | Python

class Node(object):
    
    def __init__(self,value):
        
        self.value = value
        self.nextnode = None
def reverse(head):
    
    # Set up current,previous, and next nodes
    current = head
    previous = None
    nextnode = None

    # until we have gone through to the end of the list
    while current:
        nextnode = current.nextnode

        # Reverse the pointer ot the next_node
        current.nextnode = previous

        # Go one forward in the list
        previous = current
        current = nextnode

    return previous

# Create a list of 4 nodes
a = Node(1)
b = Node(2)
c = Node(3)
d = Node(4)
e = Node(5)

# Set up order a,b,c,d with values 1,2,3,4
a.nextnode = b
b.nextnode = c
c.nextnode = d
d.nextnode = e

print a.nextnode.value
print b.nextnode.value
print c.nextnode.value
print d.nextnode.value
print e.nextnode

reverse(a)

print 'after reverse----'
print e.nextnode.value
print d.nextnode.value
print c.nextnode.value
print b.nextnode.value
print a.nextnode

Doubly Linked List | Python

Implementation of Doubly Linked List in Python

class DoublyLinkedList(object):

	def __init__(self,val):

		self.value = val
		self.next_node = None
		self.prev_node = None

a = DoublyLinkedList(1)
b = DoublyLinkedList(2)
c = DoublyLinkedList(3)

a.next_node = b
b.prev_node = a

b.next_node = c
c.prev_node = b