python模拟队列和堆栈(列表练习)
##################################queue######################################### #!/usr/bin/env python 'use list as a queue' #define a void list as a void queue queue = [] #define in queue function def enQ(): queue.append(raw_input('Enter New String: ').strip()) #define out queue function def deQ(): #judge queue whether viod if len(queue) == 0: print('Can not pop from an empty queue!') else: print('Removed' ,queue.pop(0)) #define show queue function def viewQ(): print(queue) #define a dictionary to chose opration function cmds = {'e':enQ,'d':deQ,'v':viewQ} #define a funtion to show menu def showMenu(): pr = ''' (E)nqueue (D)equeue (V)iew (Q)uit Enter choice:''' #double while circle make program always run while True: while True: try: #use to print menu information and get valid choice number(no space, just one bit , lower) choice = raw_input(pr).strip()[0].lower() except(EOFError,KeyboardInterrupt,IndexError): #if get a invalid value,return 'q' choice = 'q' print('You picked: %s '% choice) if choice not in 'devq': print('Invalid option, try again!') else: break if choice == 'q': break #call functions by dictionary cmds[choice]() #main function if __name__ == '__main__': showMenu() ##################################stack###################################### #!/usr/bin/env python 'this program use list as a stack' stack = [] def pushit(): 'input stack ' stack.append(raw_input('Enter New Strings: ').strip()) def popit(): 'output stack' if len(stack) == 0: print('Can not pop from an empty stack!') else: print('removed [',stack.pop(),']') def viewStack(): print(stack) CMDs = {'u': pushit, 'o': popit, 'v': viewStack} def showMenu(): pr = ''' p(U)sh p(O)p (V)iew (Q)uit Enter Choice: ''' while True: while True: try: choice = raw_input(pr).strip()[0].lower() print(choice) except(EOFError.KeyboardInterrupt,IndexError): choice = 'q' print('you picked: %s ' % choice) if choice not in 'uovq': print('Invalid option, try again') else: break if choice == 'q': break CMDs[choice]() if __name__ == '__main__': showMenu()
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