if USD is not selected currency

Question

I am making a small project currency converter. When I convert USD to any other currency, it correctly displays the correct answer. If I choose another currency except for USD, the result comes as the same digit/amount as I put. But I want to convert entered currency into to_currency. How can I fix it?

# Import the modules needed
from tkinter import *
from tkinter import ttk
from tkinter import messagebox
import requests

url = 'https://v6.exchangerate-api.com/v6/8a0fcd7df32ea4704f4fc48d/latest/USD'
response = requests.get(url)
response.raise_for_status()
data = response.json()
currency_key = data['conversion_rates']


def convert():
    input_02.delete(0, END)
    amount = input_01.get()
    if amount == "":
        messagebox.showinfo(title="Invalid", message="Please Insert the Amount")
        return False
    currency_02 = to_currency.get()
    for i, j in currency_key.items():
        var01 = i.upper()
        var02 = currency_02.upper()
        if var01 in var02:
            try:
                if from_currency.get() != 'USD':
                    amount = float(amount)/j
                    value = amount*j
                    input_02.insert(0, f"{value}")
                else:
                    value = j*float(amount)
                    value = round(value, 4)
                    input_02.insert(0, f"{value}")
            except ValueError:
                messagebox.showinfo(title="Invalid", message="Please insert Amount in Digits")



window = Tk()
window.title('Currency Converter!')
window.iconbitmap('currency.ico')
window.config(padx=50, bg='#0CA7D3')

label_01 = Label(text="Currency Converter GUI", bg='#0CA7D3', foreground='white', font=("arial", 20, "bold"))
label_01.grid(column=0, row=0, columnspan=3, pady=15)

from_currency = StringVar()
from_currency.set("  USD  ")
dropdown_01 = ttk.Combobox(textvariable=from_currency, width=16, font=("arial", 10, "bold"), state='enable',
                           values=list(currency_key))
dropdown_01.grid(column=0, row=1)

input_01 = Entry(font=("arial", 10, "bold"), width=19)
input_01.focus()
input_01.grid(column=0, row=2, pady=5)

to_currency = StringVar()
to_currency.set("  PKR  ")
dropdown_02 = ttk.Combobox(textvariable=to_currency, width=16, font=("arial", 10, "bold"), state='readonly',
                           values=list(currency_key))
dropdown_02.grid(column=2, row=1)

input_02 = Entry(font=("arial", 10, "bold"), width=19)
input_02.grid(column=2, row=2, pady=5)

button = Button(text="Convert", command=convert, width=8, bg='#0084AB', fg='white', font=("arial", 10, "bold"))
button.grid(column=0, row=3, pady=20)


window.mainloop()

Answer 1

The rate for from_currency to to_currency can be calculated by:

rate = currency_key[to_currency.get()] / currency_key[from_currency.get()]

Below is the modified convert():

def convert():
    amount = input_01.get().strip()
    if amount == "":
        messagebox.showinfo(title="Invalid", message="Please insert the amount")
        return False
    try:
        rate = currency_key[to_currency.get()] / currency_key[from_currency.get()]
        value = float(amount) * rate
        input_02.delete(0, "end")
        input_02.insert("end", value)
    except ValueError:
        messagebox.showinfo(title="Invalid", message="Please insert amount in digits")