Building a Currency Converter with Python: A Step-by-Step Guide

Introduction:

• The Importance of Currency Conversion:
• Currency conversion is a common requirement in global financial transactions, travel, and international commerce.
• Building a currency converter using Python can simplify and automate the process.

Here is my currency converter python code:

import tkinter as tk
from tkinter import ttk
import requests, json
from bs4 import BeautifulSoup as bs
from tkinter import *

class CurrencyConverter():
    def __init__(self,url):
        self.data= requests.get(url).json()
        self.currencies = self.data['rates']
        
m = tk.Tk()
m.title('Currency Converter')
m.geometry("300x150")
m.eval('tk::PlaceWindow . center')

Label(m, text='Source Currency  :').grid(row=0)
Label(m, text='Target Currency  :').grid(row=1)
Label(m, text='Amount  :').grid(row=2)
Label(m, text='Result  :').grid(row=8)
label=Label(m, text =" ").grid(row=8, column=1)

source_currency_entry = Entry(m)
target_currency_entry = Entry(m)
amount_entry = Entry(m)

source_currency_entry.grid(row=0, column=1)
target_currency_entry.grid(row=1, column=1)
amount_entry.grid(row=2, column=1)


def clear(): 
  source_currency_entry.delete(0, END)
  target_currency_entry.delete(0, END)
  amount_entry.delete(0, END)


def convert():
    source_currency = source_currency_entry.get()
    target_currency = target_currency_entry.get()
    amount = float(amount_entry.get())
    
    response = requests.get(f"https://www.x-rates.com/calculator/?from={source_currency}&to={target_currency}&amount=1")
    soup = bs(response.text, "html.parser")
    
    text1 = soup.find(class_="ccOutputTrail").previous_sibling
    text2 = soup.find(class_="ccOutputTrail").get_text(strip=True)
    rate = "{}{}".format(text1,text2)
    result=amount*float(rate)
    #return result

    res = Label(m, text =result,font='Helvetica 10 bold')   
    res.grid(row=8, column=1)
    
           
button = tk.Button(m, text='Convert', command=convert)
button.grid(row=3, column=1)

button2 = tk.Button(m, text='Clear', command=clear)
button2.grid(row=4, column=1)

m.mainloop()

Now let’s run our code and make an example:

Let’s convert 10000 dollar to Argentine pesos:

Section 1: Setting Up the Project

1.1 Environment Setup:

• Installing Python and setting up a development environment.
• Utilizing a virtual environment to keep project dependencies isolated.

1.2 Library Installation:

• Introduction to the required libraries:
• tkinter: A standard GUI library for creating the user interface.
• requests: A library for making HTTP requests to fetch currency conversion rates.
• json: A built-in library for working with JSON data.
• bs4 (BeautifulSoup): A library for parsing HTML and extracting data from websites.

Section 2: Implementing the CurrencyConverter Class

2.1 Fetching Currency Rates:

• Understanding the API used to fetch live currency rates.
• Utilizing the requests library to make a GET request and obtain the rates in JSON format.
• Extracting the rates from the API response using the json library.

Section 3: Building the User Interface

3.1 Creating the Main Window:

• Importing the necessary modules from tkinter.
• Setting up the main window with a title and dimensions.
• Centering the window on the screen.

3.2 Adding Labels and Entry Fields:

• Creating labels and entry fields for source currency, target currency, and amount.
• Utilizing the grid() method to organize the layout within the window.

3.3 Implementing the Conversion Function:

• Defining the convert() function to perform the currency conversion.
• Retrieving user input from the entry fields.
• Using the requests library to fetch the current conversion rate from a web page.
• Parsing the HTML response using BeautifulSoup to extract the conversion rate.
• Performing the currency conversion calculation.

3.4 Displaying the Result:

• Adding a label to display the converted amount.
• Updating the label with the calculated result.

Section 4: Interacting with the Web

4.1 Making HTTP Requests:

• Discussing the requests library in more detail.
• Exploring different types of requests and HTTP methods.

4.2 Parsing HTML with BeautifulSoup:

• Understanding the structure of HTML documents.
• Utilizing BeautifulSoup to extract specific elements and data from HTML.

Conclusion:

Recap of the process:

• Setting up the project and installing the necessary libraries.
• Implementing the currency converter logic using Python.
• Building the user interface with tkinter.
• Interacting with the web to fetch live conversion rates.

The benefits of building a currency converter with Python:

• Automation and convenience in currency conversion tasks.
• Potential for customization and integration with other financial applications.

See you in the next articles :)