88 lines
2.9 KiB
Python
88 lines
2.9 KiB
Python
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# -----------------------------------------------------------------------------
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# logarithm.py
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# -----------------------------------------------------------------------------
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"""
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Create a GUI application to compute logarithms using the Tkinter module.
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"""
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try:
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# This will work in Python 2.7
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import Tkinter
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except ImportError:
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# This will work in Python 3.5
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import tkinter as Tkinter
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# -----------------------------------------------------------------------------
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# Create main window.
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# -----------------------------------------------------------------------------
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root = Tkinter.Tk()
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# Create two text boxes and pack them in.
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greeting = Tkinter.Label(text="Hello, world!")
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greeting.pack(side='top')
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advertisement = Tkinter.Label(text="I am logarithm computing GUI.")
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advertisement.pack(side='top')
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# Define a function to close the window.
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def quit(event=None):
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root.destroy()
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# Cause pressing <Esc> to close the window.
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root.bind('<Escape>', quit)
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# Create a button that will close the window.
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button = Tkinter.Button(text="Exit", command=quit)
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button.pack(side='bottom', fill='both')
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# -----------------------------------------------------------------------------
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# Create a frame within the main window.
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# -----------------------------------------------------------------------------
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# The frame will contain the widgets needed to do a calculation.
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# Each widget in "frame" is created with "frame" as its first argument.
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frame = Tkinter.Frame(root)
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frame.pack(side='top')
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# Create a text box that explains the calculation.
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invitation = Tkinter.Label(frame, text="The natural logarithm of")
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invitation.pack(side='left')
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# Define an input variable and add an entry box so the user can change its value.
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x = Tkinter.StringVar()
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x.set('2.71828')
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x_entry = Tkinter.Entry(frame, width=8, textvariable=x)
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x_entry.pack(side='left')
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# Define an output variable and a function to compute its value.
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y = Tkinter.StringVar()
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def compute_y(event=None):
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from math import log
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# Get x and y from outside the function.
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global x, y
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# Get the string value of the x StringVar and convert it to a float.
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x_value = float(x.get())
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# Compute the floating point value of y.
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y_value = log(x_value)
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# Convert this to a formatted string, and store it in the y StringVar.
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y.set('%.6f' % y_value)
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# Bind an event to the x_entry box: pressing <Enter> will calculate the
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# logarithm of whatever number the user has typed.
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x_entry.bind('<Return>', compute_y)
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# Create a button to perform the calculation and pack it into the frame.
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compute = Tkinter.Button(frame, text=' is ', command=compute_y)
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compute.pack(side='left')
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# Create a text box that displays the value of the y StringVar.
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y_label = Tkinter.Label(frame, textvariable=y, width=8)
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y_label.pack(side='left')
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# -----------------------------------------------------------------------------
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# Activate the window.
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# -----------------------------------------------------------------------------
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root.mainloop()
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