Simple Calculator

calculator/calculator2.py

@@ -0,0 +1,55 @@
+# Inspirado no programa 'clac1.py' do livro "Python and Tkinter Programming" de John E.Grayson
+from tkinter import *
+
+def frame(root, side):
+    w = Frame(master=root)
+    w.pack(side=side, expand=True, fill=BOTH, padx=(5, 0))
+    return w
+
+def button(root, text, side, command=None, **kw):
+    w = Button(master=root, text=text,
+               command=command, relief=RIDGE, **kw)
+    w.pack(side=side, expand=True, fill=BOTH)
+    return w
+
+root = Frame()
+display = StringVar()
+frame_top = Frame(root,)
+frame_top.pack(side=TOP, fill=BOTH, expand=YES)
+Entry(master=frame_top, relief=SUNKEN,
+      textvariable=display).pack(side=LEFT, expand=YES, fill=BOTH, padx=5, pady=2)
+Button(frame_top, text="C",
+       command=lambda w=display: w.set(''),
+       bg="red", fg="white", relief=RIDGE).pack(side=RIGHT, expand=False, padx=2)
+
+
+for i in "987+ 654- 321* 0d./".split():
+    frame2buttons = frame(root, TOP)
+    for char in i:
+        if char == "d":
+            button(frame2buttons, "00", LEFT,
+                   lambda w=display: w.set(w.get()+"00"))
+        else:
+
+            button(frame2buttons,char,LEFT,
+                   lambda w=display, c='%s' % char: w.set(w.get()+c))
+
+
+def result(w, e=None):
+    s = w.get()
+    if '%' in s:
+        index = list(s).index('%')
+        list_s = list(s)
+        list_s.insert(0, '(')
+        list_s.insert(index+1, ')/100')
+        list_s[index+2] = '*'
+        s = ''.join(list_s)
+
+    w.set(eval(s))
+
+frame_bottom = frame(root, BOTTOM)
+button(frame_bottom, "=", LEFT, command=lambda w=display: result(w), bg="red", fg="white")
+Button(master=frame_bottom, text="%", relief=RIDGE, command=lambda w=display: w.set(w.get()+"%")).pack(side=LEFT, expand=False)
+
+root.pack(side=TOP, fill=BOTH, expand=True)
+root.mainloop()