I always have the challenge of reading. Whether it is technical documentation, general documentation or anything. If I remember correctly, the last time I read something continuously was when I was in my school and college days. And that too nothing extraordinary but weekly magazines like Anandha Vikatan/Kumudham and very rarely newspapers. That got improved when I started my work and regularly read the news headlines from “The Hindu”. That’s all the reading I have got in my entire life. I have this habit of purchasing the books and will think.. One day.. that One day will come and I will become a Pro Reader and I will read all the books. But that did not happened till date.

So I was pouring all these frustration in the “#Kaniyam” IRC chat along with some more concerns like I have trouble planning things. I use to start with one and if I come across something else I will leave whatever I was doing and start doing the new item and it goes on and on. Then Srini from the Kaniyam IRC group suggested various ideas to give a try and one such idea is reading this book called “Eat the Frog”.

I wouldn’t say the book has changed me completely overnight but the practice of reading a few pages continuously gives a sense of satisfaction. I am not saying I have read 20-30 pages continuously instead I planned to complete a chapter whenever i start.

The book as such has got things we often hear or see elsewhere but more importantly it is structured. When I say it is structured, it starts with the topic explanation on why the author has named the book as “Eat the Frog”.

In our daily life if we think eating a frog is one of our primary task. How will one plan. Because eating a frog is not that easy. And that too if you have more than one frog how will one plan to do that. Here the author compares the frog to that of the tasks we have in a day. Not all tasks are difficult as eating a frog. So if we have frogs of different size and the task is to complete eating them all in a day. How will one approach. He will target finishing the bigger one then the next then the next and it goes on. By the time one completes the biggest he will get the confidence to go for the next smaller sized frog.

This analogy works the same way for our daily tasks. Rather than picking the easy ones and save the bulk or harder tasks for a later time, plan to finish the harder or most difficult task first which will help us move with the next difficult task with a lot more confidence.

This was primarily discussed on Chapter 1. After reading this I wanted to see if this approach works. I started implementing it immediately but listing the items it wanted to complete for that day. And in that I sorted those items based on the difficulty(in terms of time). I did not create an exhaustive list rather 4 tasks for that day and out of which 2 are time taking or difficult task.

End of the day I was able to complete the top 2 leaving the remaining 2. I still felt happy because i completed the top 2 which is harder. And moved the pending 2 to next day and kept the priority as top for those 2.

So far it is working and I will continue to write about the other chapters as I complete reading them.

“Let us all start get into the habit of reading and celebrate..happy reading”

I was so much into using the fpdf module that I almost gave up on this particular task. The challenge I faced is that, I can pass the entire content to the createpdf function but the formatting went completely off track. The other option i was thinking is that send lines one after the other to a text file and finally convert that text file to a pdf. But even that task looked out of my ability. I paused this for a few days and poured in all my frustration not just with this task but with all the other challenges in my IRC channel #kaniyam where I received awesome suggestions from Shrinivasan.T, again not just with the solution to this problem but in general about overcoming the challenges in reading.

Took a deep breath and started fresh and came across a resource where they implemented pdf creation using a different module called reportlab where there was a solution to insert the text to display into a python list and get the entries from the list using a loop and add it to the pdf construct. I was able to finally complete the first step using that module.

Here is the code block

	import configparser
	import psycopg2
	import psycopg2.extras
	from reportlab.pdfgen import canvas
	from reportlab.pdfbase import pdfmetrics
	from reportlab.lib import colors
	config = configparser.ConfigParser()
	config.read('config.ini')
	hostname = config['ConnPostgres']['hostname']
	database = config['ConnPostgres']['database']
	port_id = config['ConnPostgres']['port_id']
	pwd = config['ConnPostgres']['pwd']
	username = config['ConnPostgres']['username']
	bill=0
	final_bill_txt = ''
	textlines = []
	def fetch_BillAmount(in_item,in_qty):
	conn=None
	cur=None
	try:
	conn = psycopg2.connect(
	host = hostname,
	dbname = database,
	user = username,
	password = pwd,
	port=port_id
	)
	cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
	select_script = '''Select ItemCode, ItemName, ItemPrice from StoreItems where ItemCode= %s'''
	cur.execute(select_script,(in_item,))
	dict_items = dict()
	dict_items = cur.fetchall()
	for dictItem in dict_items:
	bill_amount = in_qty * dictItem['itemprice']
	return dictItem['itemname'],bill_amount
	except Exception as error:
	print(error)
	finally:
	if conn is not None:
	conn.close()
	if cur is not None:
	cur.close()
	def billing():
	global bill,textlines
	in_item = input('Enter the item code:')
	in_qty = int(input('Enter the quantity:'))
	item_name,calc_bill = fetch_BillAmount(in_item,in_qty)
	bill = bill + calc_bill
	print(f'The Bill amount for {in_qty} of {item_name} : ${calc_bill}')
	textlines.append(f'The Bill amount for {in_qty} of {item_name} : ${calc_bill}')
	def write2Pdf(lsTextline):
	pdf = canvas.Canvas('Demo.pdf')
	pdf.setFillColorRGB(0,0,255)
	pdf.setFont("Courier-Bold",24)
	pdf.drawCentredString(290,720,"Shoppers Mart")
	pdf.line(30,710,550,710)
	text = pdf.beginText(40,680)
	text.setFont("Courier",18)
	for line in lsTextline:
	text.textLine(line)
	pdf.drawText(text)
	pdf.save()
	print('Welcome to Shoppers Mart')
	first_login = 'Y' #default initial condition
	i=1 #default loop initial value
	while i != 0:
	if first_login != 'Y':
	in_Opt = input('Do you wish to continue shopping?(Y/N)')
	if first_login == 'Y' or in_Opt == 'Y':
	billing()
	first_login = 'N'
	else:
	print(f'Your total bill amount is ${bill}')
	textlines.append(f'Your total bill amount is ${bill}')
	print('Thank you for shopping!')
	textlines.append('Thank you for shopping!')
	write2Pdf(textlines)
	break

view raw storeBillingApp_PdfOutput.py hosted with ❤ by GitHub

	from reportlab.pdfgen import canvas
	from reportlab.pdfbase import pdfmetrics
	from reportlab.lib import colors
	textlines = ['Sample text 1','Sample text 2','Sample text 3','Sample text 4']
	pdf = canvas.Canvas('Demo.pdf')
	text = pdf.beginText(40,680)
	text.setFont("Courier",18)
	for line in textlines:
	text.textLine(line)
	pdf.drawText(text)
	pdf.save()

view raw pdfGenDemo.py hosted with ❤ by GitHub

The below program uses configparser module to secure the DB config or the connection parameters. In the earlier programs the DB connections were all exposed and kept in the same program. In this program, DB connection is saved under a different file named “config.ini” and the parameters were called with the help of “ConfigParser”.

	import configparser#Note: All lowercase
	import psycopg2 #module to connect the postgreSQL DB
	import psycopg2.extras #module to fetch the data from DB table in the form of Dictionaries
	config = configparser.ConfigParser()#Note:the calling method is a camel case
	config.read('config.ini')
	in_Item2buy = input('Enter the itemcode required:')
	in_ItemQty = int(input('Enter the quantity:'))
	hostname = config['ConnPostgres']['hostname']
	database = config['ConnPostgres']['database']
	port_id = config['ConnPostgres']['port_id']
	pwd = config['ConnPostgres']['pwd']
	username = config['ConnPostgres']['username']
	conn=None
	cur=None
	try:
	conn = psycopg2.connect(
	host = hostname,
	dbname = database,
	user = username,
	password = pwd,
	port=port_id
	)
	cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
	#cur = conn.cursor()
	select_script = '''Select ItemCode, ItemName, ItemPrice from StoreItems where ItemCode= %s'''
	cur.execute(select_script,(in_Item2buy,))
	dict_items = dict()
	dict_items = cur.fetchall()
	for dictItem in dict_items:
	#print(dictItem) #test print statement to verify the dict of items for the given input
	bill_amount = in_ItemQty * dictItem['itemprice']
	print('The bill amount for ',dictItem['itemname'],':$',bill_amount) # Print the price
	#conn.commit() #not required for this program as we are not doing any DML
	except Exception as error:
	print(error)
	finally:
	if conn is not None:
	conn.close()
	if cur is not None:
	cur.close()

view raw configparserDemo.py hosted with ❤ by GitHub

After many unsuccessful attempts, I was able to send the output from my previous code block to a pdf file. Definitely a huge learning in terms of how to properly import the necessary packages how to troubleshoot the error messages and find out the deprecated syntax and replace with the updated ones etc.,

here is the snapshot of the exceptions i received during the process of fixing

And here I am with a screenshot with no exception mentioned

My final code snippet below:

	import psycopg2
	import psycopg2.extras
	from fpdf import FPDF
	from fpdf.enums import XPos, YPos
	def fetch_BillAmount(in_item,in_qty):
	hostname = 'localhost'
	database = 'deptstore'
	port_id = 5432
	pwd = 'admin@1234'
	username = 'postgres'
	conn=None
	cur=None
	try:
	conn = psycopg2.connect(
	host = hostname,
	dbname = database,
	user = username,
	password = pwd,
	port=port_id
	)
	cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
	#cur = conn.cursor()
	select_script = '''Select ItemCode, ItemName, ItemPrice from StoreItems where ItemCode= %s'''
	cur.execute(select_script,(in_item,))
	dict_items = dict()
	dict_items = cur.fetchall()
	for dictItem in dict_items:
	#print(dictItem) #test print statement to verify the dict of items for the given input
	bill_amount = in_qty * dictItem['itemprice']
	return dictItem['itemname'],bill_amount
	except Exception as error:
	print(error)
	finally:
	if conn is not None:
	conn.close()
	if cur is not None:
	cur.close()
	bill=0
	final_bill_txt = ''
	def billing():
	global bill,final_bill_txt
	in_item = input('Enter the item code:')
	in_qty = int(input('Enter the quantity:'))
	item_name,calc_bill = fetch_BillAmount(in_item,in_qty)
	bill = bill + calc_bill
	print(f'The Bill amount for {in_qty} of {item_name} : ${calc_bill}')
	final_bill_txt = final_bill_txt + (f'The Bill amount for {in_qty} of {item_name} : ${calc_bill}\n')
	def write2Pdf(in_text):
	pdf = FPDF()
	pdf.add_page()
	pdf.set_font("helvetica", size = 15)
	pdf.cell(200, 10, text = "Shoppers Mart",new_x=XPos.LEFT, new_y=YPos.NEXT, align = 'C')
	pdf.cell(200, 10, text = final_bill_txt,new_x=XPos.LEFT, new_y=YPos.NEXT,align = 'L')
	pdf.output("ShoppersReceipt.pdf")
	print('Welcome to Shoppers Mart')
	first_login = 'Y' #default initial condition
	i=1 #default loop initial value
	while i != 0:
	if first_login != 'Y':
	in_Opt = input('Do you wish to continue shopping?(Y/N)')
	if first_login == 'Y' or in_Opt == 'Y':
	billing()
	first_login = 'N'
	else:
	print(f'Your total bill amount is ${bill}')
	final_bill_txt = final_bill_txt + (f'\n\n\n\nYour total bill amount is ${bill}\n\n\n\n\n\n''Thank you for shopping!')
	print(final_bill_txt)
	write2Pdf(final_bill_txt)
	#print('Thank you for shopping!')
	break

view raw billingMulipleItem_db_pdf1.py hosted with ❤ by GitHub

PDF Output:

I have been working on a task where I need to collect input(eg: Item code) from user, query the database to fetch the price and then to calculate the bill amount and print the output. I was able to do this successfully. Then comes the next learning where it was asked to feed this output into a pdf file.

I thought it would be a simple task where we will be importing a package and use that to write the output into a pdf file. I was proved terribly wrong.

I found a link where it was asked to use FPDF as a package to import and use it in the code. When I tried to install on my linux machine i kept getting the below error:

As usual I did not get the signal to use my senses rather my IT mindset to start searching like “unable to install fpdf” I went link over link over link but ended up with the same error. It started from 4:45 am this morning and finally around 6 am I decided to learn from “mistakes”. My senses started to work, especially the eyes and the sense of seeing

I carefully went through the exception, yet my IT brain started to override and asked me to just copy and paste the command from the link. This is classic

It was mentioned something like this:

If you wish to install a non-Debian packaged Python application,
it may be easiest to use pipx install xyz, which will manage a
virtual environment for you. Make sure you have pipx installed.

Then I tried exactly the same command but this time my brain partially worked it seems so replaced xyz to fpdf:

Thank god. Computers aren’t meant to use abusive language. hehehehe

Then I went back to the pavillion and started searching other links where they asked to install jinja2( i tried that too). And in the same error message, it was mentioned to consider virtual environment, why to leave that, yes I tried that too.

Somehow I got through installing the virtual environment. But after that, I do not know what to do or interpret the error details. So the failure streak continues

Finally…………………………….

My senses were awaken And the brain started to work as if I had an espresso shot This time i tried the below

Though it failed again. As I said, “I learnt from mistakes(error message)”. And this happened after that.

Moral of the story:

it was told by many people whom I have interacted so far that always “read through the error message. 99% it has got enough information to change and rerun the code or installation” But because of my inherited IT brain I have avoided that till today. But from today, I am planning to change…and “to learn from mistakes(errors)” always.

Thanks for reading my funny story!

	import psycopg2
	import psycopg2.extras
	def fetch_BillAmount(in_item,in_qty):
	hostname = 'localhost'
	database = 'deptstore'
	port_id = 5432
	pwd = 'admin@1234'
	username = 'postgres'
	conn=None
	cur=None
	try:
	conn = psycopg2.connect(
	host = hostname,
	dbname = database,
	user = username,
	password = pwd,
	port=port_id
	)
	cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
	#cur = conn.cursor()
	select_script = '''Select ItemCode, ItemName, ItemPrice from StoreItems where ItemCode= %s'''
	cur.execute(select_script,(in_item,))
	dict_items = dict()
	dict_items = cur.fetchall()
	for dictItem in dict_items:
	#print(dictItem) #test print statement to verify the dict of items for the given input
	bill_amount = in_qty * dictItem['itemprice']
	return bill_amount
	except Exception as error:
	print(error)
	finally:
	if conn is not None:
	conn.close()
	if cur is not None:
	cur.close()
	bill=0
	def billing():
	global bill,itemized_bill
	in_item = input('Enter the item code:')
	in_qty = int(input('Enter the quantity:'))
	calc_bill = fetch_BillAmount(in_item,in_qty)
	bill = bill + calc_bill
	print('Welcome to Shoppers Mart')
	first_login = 'Y' #default initial condition
	i=1 #default loop initial value
	while i != 0:
	if first_login != 'Y':
	in_Opt = input('Do you wish to continue shopping?(Y/N)')
	if first_login == 'Y' or in_Opt == 'Y':
	billing()
	first_login = 'N'
	else:
	print_txt = 'Your total Bill amount : ',bill
	print('Your total Bill amount : ',bill)
	print('Thank you for shopping!')
	break

view raw billingMulipleItem_db.py hosted with ❤ by GitHub

In this program, the user can get the input about what item is required from the store and how many quantities. Based on the input the dynamic query returns the price of the item selected and the bill amount is calculated and printed.

	import psycopg2 #module to connect the postgreSQL DB
	import psycopg2.extras #module to fetch the data from DB table in the form of Dictionaries
	in_Item2buy = input('Enter the itemcode required:')
	in_ItemQty = int(input('Enter the quantity:'))
	hostname = 'localhost'
	database = 'deptstore'
	port_id = 5432
	pwd = 'admin@1234'
	username = 'postgres'
	conn=None
	cur=None
	try:
	conn = psycopg2.connect(
	host = hostname,
	dbname = database,
	user = username,
	password = pwd,
	port=port_id
	)
	cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
	#cur = conn.cursor()
	select_script = '''Select ItemCode, ItemName, ItemPrice from StoreItems where ItemCode= %s'''
	cur.execute(select_script,(in_Item2buy,))
	dict_items = dict()
	dict_items = cur.fetchall()
	for dictItem in dict_items:
	#print(dictItem) #test print statement to verify the dict of items for the given input
	bill_amount = in_ItemQty * dictItem['itemprice']
	print('The bill amount for ',dictItem['itemname'],':$',bill_amount) # Print the price
	#conn.commit() #not required for this program as we are not doing any DML
	except Exception as error:
	print(error)
	finally:
	if conn is not None:
	conn.close()
	if cur is not None:
	cur.close()

view raw billingSingleItem_db.py hosted with ❤ by GitHub

	import psycopg2 #module to connect the postgreSQL DB
	import psycopg2.extras #module to fetch the data from DB table in the form of Dictionaries
	hostname = 'localhost'
	database = 'deptstore'
	port_id = 5432
	pwd = 'admin@1234'
	username = 'postgres'
	conn=None
	cur=None
	try:
	conn = psycopg2.connect(
	host = hostname,
	dbname = database,
	user = username,
	password = pwd,
	port=port_id
	)
	cur = conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor)
	#cur = conn.cursor()
	select_script = '''Select ItemCode, ItemName, ItemPrice from StoreItems'''
	cur.execute(select_script)
	dict_items = dict()
	dict_items = cur.fetchall()
	for items in dict_items:
	print(items)
	#conn.commit() #not required for this program as we are not doing any DML
	except Exception as error:
	print(error)
	finally:
	if conn is not None:
	conn.close()
	if cur is not None:
	cur.close()

view raw retrieveDataFromPgDB.py hosted with ❤ by GitHub

	#simple billing app using csv read functionality
	#PRE_REQUISITE: Place the file "StoreItems.csv" in the current Python folder or specify the complete file path
	import csv
	in_ItemCode = input('Enter the item code:')
	in_ItemQty = int(input('Enter the quantity required: '))
	with open('StoreItems.csv','r') as file1:
	reader1 = csv.DictReader(file1)
	for row in reader1:
	if row['ItemCode']==in_ItemCode:
	print('The bill amount for',row['ItemName'],'is:$',int(row['ItemPrice'])*in_ItemQty)

view raw billingAppCsv1.py hosted with ❤ by GitHub

create a project – billing application for a grocery store. define the items and prices as a dictionary.get item number and quantity as input.in w while loop, till the itemnumber = 0.for now on the billing application, define the prices as a dictionary. later, read the price data from a CSV file

	''' Function to calculate the billing for the purchased item'''
	def billing_app():
	item_to_buy = int(input('Enter the itemcode[Rice-1011 Dhal-1012 Oil-1013 Spices-1014]: '))
	if item_to_buy in dictStoreItems.keys():
	qty_to_buy = float(input('Enter the quamtity: '))
	print('The total bill amount for ',item_to_buy,': ',qty_to_buy*dictStoreItems[item_to_buy])
	else:
	print('Invalid Item Code')
	dictStoreItems = {1011:15,1022:10,1033:5,1044:3,1055:2}
	input('Enter the membership number: ')
	first_time_login = 'Y' #used to identify the first time a shopper logging in
	i=1 #looping criteria
	in_Opt='Y' #defaulting the option to Y for the first time shopping
	while i != 0:
	if first_time_login != 'Y':
	in_Opt = input('Do you wish to continue shopping?(Y/N)')
	if in_Opt == 'Y' or first_time_login == 'Y':
	billing_app()
	first_time_login = 'N'
	else:
	print('Thank you for shopping!')
	break

view raw billing_app.py hosted with ❤ by GitHub

	#nested dictionaries
	Bill_Total = 0
	def billing_app():
	item_to_buy = int(input('Enter the itemcode[Rice-1011 Dhal-1012 Oil-1013 Spices-1014]: '))
	if item_to_buy in dictStoreItems.keys():
	qty_to_buy = float(input('Enter the quamtity: '))
	print('The Bill amount for ',dictStoreItems[item_to_buy]['Name'],': $',dictStoreItems[item_to_buy]['UnitPrice']*qty_to_buy)
	global Bill_Total
	Bill_Total = Bill_Total + dictStoreItems[item_to_buy]['UnitPrice']*qty_to_buy
	else:
	print('Invalid Item Code')
	#below is the nested dictionary containing Product code, name and unit price
	dictStoreItems = {1011:{'Name':'Rice','UnitPrice':15},1012:{'Name':'Dhal','UnitPrice':10},1013:{'Name':'Oil','UnitPrice':5},1014:{'Name':'Salt','UnitPrice':3}}
	input('Enter the membership number: ')#dummy input
	print('****Welcome to Payilagam Shoppers Mart*****')#dummy output
	first_time_login = 'Y' #default initial condition
	i=1 #default loop initial value
	while i != 0:
	if first_time_login != 'Y':
	in_Opt = input('Do you wish to continue shopping?(Y/N)')
	if first_time_login == 'Y' or in_Opt == 'Y':
	billing_app()
	first_time_login = 'N'
	else:
	print('Your total Bill amount : ',Bill_Total)
	print('Thank you for shopping!')
	break

view raw billing_app_nested_dict.py hosted with ❤ by GitHub

Basic calculator app code:

Alternate method by using function/method:

Code repo:

	in_Option = input('Enter the option 1.Sum 2.Difference 3.Multiplcation 4.Division:')
	in_Param1 = input('Enter the parameter 1:')
	in_Param2 = input('Enter the parameter 2:')
	def switch(in_Option):
	if in_Option == '1':
	print('You entered the option for Addition and the sum of the 2 inputs are: ',int(in_Param1)+int(in_Param2))
	return
	if in_Option == '2':
	if in_Param1>in_Param2:
	print('You entered the option for difference and the difference of the 2 inputs are: ',int(in_Param1)-int(in_Param2))
	return
	else:
	print('You entered the option for difference and the difference of the 2 inputs are: ',int(in_Param2)-int(in_Param1))
	return
	if in_Option == '3':
	print('You entered the option for Product and the Product of the 2 inputs are: ',int(in_Param1)*int(in_Param2))
	return
	if in_Option == '4':
	print('You entered the option for Division and the Product of the 2 inputs are: ',int(in_Param1)/int(in_Param2))
	return
	else:
	print('Invalid option selected')
	return
	switch(in_Option)

view raw calc_app_basic.py hosted with ❤ by GitHub

	def calc_app(input, param1, param2):
	if input == 1:
	print('Sum=',param1+param2)
	elif input ==2 and param1 > param2:
	print('Difference=',param1-param2)
	elif input == 2 and param2 > param1:
	print('Difference=',param2 – param1)
	elif input == 3:
	print('Product=',param1*param2)
	elif input ==4:
	print('Division=',param1/param2)
	in_Option = int(input('Enter the option[1-Add 2-Subtract 3-Multiply 4-Division]: '))
	param1 = int(input('Enter the parameter 1:'))
	param2 = int(input('Enter the parameter 2:'))
	calc_app(in_Option,param1,param2)

view raw calc_app_function.py hosted with ❤ by GitHub