lwvconverter.py

from tkinter import *

# Conversion factors
unit_dict = {
    "cm" : 0.01,
    "m" : 1.0,
    "km": 1000.0,
    "feet": 0.3048,
    "miles": 1609.344,
    "inches": 0.0254,
    "grams" : 1.0,
    "kg" : 1000.0,
    "quintals": 100000.0,
    "tonnes" : 1000000.0,
    "pounds" : 453.592,
    "sq. m" : 1.0,
    "sq. km": 1000000.0,
    "are" : 100.0,
    "hectare" : 10000.0,
    "acre": 4046.856,
    "sq. mile" : 2590000.0,
    "sq. foot" : 0.0929,
    "cu. cm" : 0.001,
    "Litre" : 1.0,
    "ml" : 0.001,
    "gallon": 3.785
}

lengths = ["cm", "m", "km", "feet", "miles", "inches",]
weights = ["kg", "grams", "quintals", "tonnes", "pounds",]
temps = ["Celsius", "Fahrenheit"]
areas = ["sq. m", "sq. km", "are", "hectare", "acre", "sq. mile", "sq. foot"]
volumes = ["cu. cm", "Litre", "ml", "gallon"]

# Options for drop-down menu
OPTIONS = ["select units",
            "cm",
            "m",
            "km",
            "feet",
            "miles",
            "inches",
            "kg",
            "grams",
            "quintals",
            "tonnes",
            "pounds",
            "Celsius",
            "Fahrenheit",
            "sq. m",
            "sq. km",
            "are",
            "hectare",
            "acre",
            "sq. mile",
            "sq. foot",
            "cu. cm",
            "Litre",
            "ml",
            "gallon"]

# Main window
def lwvConverter():
    convWindow = Tk()
    convWindow.geometry("400x350")
    convWindow.title("Unit Converter")
    convWindow['bg'] = 'white'

    def ok():
        inp = float(inputentry.get())
        inp_unit = inputopt.get()
        out_unit = outputopt.get()

        cons = [inp_unit in lengths and out_unit in lengths,
                inp_unit in weights and out_unit in weights,
                inp_unit in temps and out_unit in temps,
                inp_unit in areas and out_unit in areas,
                inp_unit in volumes and out_unit in volumes]

        if any(cons):  # If both the units are of same type, do the conversion
            if inp_unit == "Celsius" and out_unit == "Fahrenheit":
                outputentry.delete(0, END)
                outputentry.insert(0, (inp * 1.8) + 32)
            elif inp_unit == "Fahrenheit" and out_unit == "Celsius":
                outputentry.delete(0, END)
                outputentry.insert(0, (inp - 32) * (5 / 9))
            else:
                outputentry.delete(0, END)
                outputentry.insert(0, round(inp * unit_dict[inp_unit] / unit_dict[out_unit], 5))

        else:  # Display error if units are of different types
            outputentry.delete(0, END)
            outputentry.insert(0, "ERROR")

    inputopt = StringVar()
    inputopt.set(OPTIONS[0])

    outputopt = StringVar()
    outputopt.set(OPTIONS[0])

    # Widgets
    inputlabel = Label(convWindow, text="Input")
    inputlabel.grid(row=0, column=0, pady=20)

    inputentry = Entry(convWindow, justify="center", font="bold")
    inputentry.grid(row=1, column=0, padx=35, ipady=5)

    inputmenu = OptionMenu(convWindow, inputopt, *OPTIONS)
    inputmenu.grid(row=1, column=1)
    inputmenu.config(font="Arial 10")

    outputlabel = Label(convWindow, text="Output")
    outputlabel.grid(row=2, column=0, pady=20)

    outputentry = Entry(convWindow, justify="center", font="bold")
    outputentry.grid(row=3, column=0, padx=35, ipady=5)

    outputmenu = OptionMenu(convWindow, outputopt, *OPTIONS)
    outputmenu.grid(row=3, column=1)
    outputmenu.config(font="Arial 10")

    okbtn = Button(convWindow, text="OK", command=ok, padx=80, pady=2)
    okbtn.grid(row=4, column=0, columnspan=2, pady=50)

    convWindow.mainloop()

if __name__ == "__main__":
    lwvConverter()