使用基本的 python 计算器，无法让我的菜单正常循环
Working on a basic python calculator and can't get my menu to loop properly
多亏了这个网站，我才能够走到这一步，作为 python 的新手，我有点卡住了。我正在尝试循环 'selection'，因此在用户进行一些数学运算后，而不是仅仅结束它会让他们选择做其他事情，直到他们 select 0 退出。我尝试了一堆其他的 try 和条件语句，但最终得到了答案，因此陷入了无限循环。
此外，我在这里很漂亮，但任何帮助都将不胜感激，而且我是一个 python 小人。如果重要的话，我正在用 python 2.7 写这篇文章。
def sum ( arg1, arg2):
total = a + b
return total;
def subtract ( arg1 , arg2):
total = a - b
return total;
def mult ( arg1, arg2):
total = a * b
return total;
def division ( arg1, arg2):
total = (a / b)
return total;
options = ["1", "2", "3", "4", "5", "0"]
print ("Please choose an option for mathing")
print ("1 for addition")
print ("2 for division")
print ("3 for subtraction")
print ("4 for multiplication")
print ("5 ")
print ("0 to exit")
#this will keep prompting the user to provide an input that is listed in 'options'
while True:
selection = input("Please select choose an option to continue")
if selection in options:
break
else:
print("Please choose a valid option")
#user input for mathing
#input will be validated as follows
a = None
while a is None:
try:
a = int(input("please provide a number for A"))
except ValueError:
print "please use a valid integer"
pass
b = None
while b is None:
try:
b = int(input("please provide a number for B"))
except ValueError:
print "please use a valid integer"
pass
#performing the operations
if selection == '1':
print "The sum is", str(sum(a, b))
elif selection == '2':
print "The quotient is", str(division(a, b))
elif selection == '3':
print "The difference is", str(subtract(a, b))
elif selection == '4':
print "The product is", str(mult(a, b))
elif selection == '0':
exit()
#this will keep prompting the user to provide an input that is listed in 'options'
while True:
selection = input("Please select choose an option to continue")
if selection in options:
if selection == 1:
sum()
if selection == 2:
subtract()
.....
if selection == 'q'
break
将逻辑更改为我上面所做的，对于选项，采取一些操作并在退出字符上中断/
只需围绕提示和计算进行循环即可。如果他们输入 0，则从最外层循环中断：
while True:
#this will keep prompting the user to provide an input that is listed in 'options'
while True:
selection = input("Please select choose an option to continue")
if selection in options:
break
else:
print("Please choose a valid option")
if selection == '0':
break
...
首先，您的代码不能像现在这样工作：
if selection == '1': #should return false
那是因为使用 input 你是在获取一个数字数量，然后将它与一个字符串进行比较。
将selection的input改为raw_input
或者像下面这样更改条件语句：
if selection == 1:
然后在整个执行块上添加一个while True，一遍又一遍地执行，直到选择0。
我会做一些事情来提高效率..
options 应该是一本字典...您的 in 在字典上比在列表上更有效率。这样做的好处是每个键的值都可以是函数方法。
例如。 options = {1: 'sum', 2: 'subtract' ..... }
然后用你的数学运算做一个class
class Calculator(object):
def sum(self, x, y):
return x + y
def subtract(self, x, y):
return x - y
#add more operations here
@staticmethod
def start():
while True:
#prompt for input and the operator
这有什么好处是在您检查选择时您可以动态调用 class 方法来大量清理代码
if selection in options:
getattr(options[selection], Calculator)(a, b)
如果你想让我解释更多，我可以完成这个例子。
对于您的循环，您可以添加一个方法来启动操作并继续循环并每次执行更多操作
这是一个基本的class你可以使用我描述的那些方法
class Calculator(object):
loop = None
calculations = 1
current_value = 0
selection = 0
options = {1: 'add', 2: 'subtract', 3: 'multiply', 4: 'divide'}
def __init__(self, loop=True):
self.loop = loop
print 'Welcome to my basic calculator!'
if not self.loop: # dont loop just execute once
self.run()
else:
while True:
self.run()
@staticmethod
def add(x, y):
return x + y
@staticmethod
def subtract(x, y):
return x - y
@staticmethod
def multiply(x, y):
return x * y
@staticmethod
def divide(x, y):
if y != 0: #cant divide by 0
return x / y
@staticmethod
def quit():
exit(0)
def run(self):
if self.calculations == 1:
self.current_value = self.prompt_user_input('please provide a number: ')
self.prompt_operator('Please choose an operator to continue\n1 for addition\n2 for subtraction\n3 for multiplication \n4 for division\n0 to quit\n')
y = self.prompt_user_input('please provide a number: ')
self.current_value = getattr(Calculator, self.options[self.selection])(self.current_value,y)
self.calculations += 1
print 'New value is: ' + str(self.current_value)
def prompt_operator(self, prompt_message):
while True:
self.selection = input(prompt_message)
if self.selection in self.options:
break
elif self.selection == 0:
self.quit()
else:
print("Please choose a valid option")
def prompt_user_input(self, prompt_message):
val = None
while val is None:
try:
val = int(input(prompt_message))
except ValueError:
print "please use a valid integer"
pass
return val
最后，要启动您的计算器，您只需调用它并传递 true 以继续循环或传递 false 以仅进行一次计算
Calculator(loop=True)
多亏了这个网站，我才能够走到这一步，作为 python 的新手，我有点卡住了。我正在尝试循环 'selection'，因此在用户进行一些数学运算后，而不是仅仅结束它会让他们选择做其他事情，直到他们 select 0 退出。我尝试了一堆其他的 try 和条件语句，但最终得到了答案，因此陷入了无限循环。
此外，我在这里很漂亮，但任何帮助都将不胜感激，而且我是一个 python 小人。如果重要的话，我正在用 python 2.7 写这篇文章。
def sum ( arg1, arg2):
total = a + b
return total;
def subtract ( arg1 , arg2):
total = a - b
return total;
def mult ( arg1, arg2):
total = a * b
return total;
def division ( arg1, arg2):
total = (a / b)
return total;
options = ["1", "2", "3", "4", "5", "0"]
print ("Please choose an option for mathing")
print ("1 for addition")
print ("2 for division")
print ("3 for subtraction")
print ("4 for multiplication")
print ("5 ")
print ("0 to exit")
#this will keep prompting the user to provide an input that is listed in 'options'
while True:
selection = input("Please select choose an option to continue")
if selection in options:
break
else:
print("Please choose a valid option")
#user input for mathing
#input will be validated as follows
a = None
while a is None:
try:
a = int(input("please provide a number for A"))
except ValueError:
print "please use a valid integer"
pass
b = None
while b is None:
try:
b = int(input("please provide a number for B"))
except ValueError:
print "please use a valid integer"
pass
#performing the operations
if selection == '1':
print "The sum is", str(sum(a, b))
elif selection == '2':
print "The quotient is", str(division(a, b))
elif selection == '3':
print "The difference is", str(subtract(a, b))
elif selection == '4':
print "The product is", str(mult(a, b))
elif selection == '0':
exit()
#this will keep prompting the user to provide an input that is listed in 'options'
while True:
selection = input("Please select choose an option to continue")
if selection in options:
if selection == 1:
sum()
if selection == 2:
subtract()
.....
if selection == 'q'
break
将逻辑更改为我上面所做的，对于选项，采取一些操作并在退出字符上中断/
只需围绕提示和计算进行循环即可。如果他们输入 0，则从最外层循环中断：
while True:
#this will keep prompting the user to provide an input that is listed in 'options'
while True:
selection = input("Please select choose an option to continue")
if selection in options:
break
else:
print("Please choose a valid option")
if selection == '0':
break
...
首先，您的代码不能像现在这样工作：
if selection == '1': #should return false
那是因为使用 input 你是在获取一个数字数量，然后将它与一个字符串进行比较。
将selection的input改为raw_input
或者像下面这样更改条件语句：
if selection == 1:
然后在整个执行块上添加一个while True，一遍又一遍地执行，直到选择0。
我会做一些事情来提高效率..
options 应该是一本字典...您的 in 在字典上比在列表上更有效率。这样做的好处是每个键的值都可以是函数方法。
例如。 options = {1: 'sum', 2: 'subtract' ..... }
然后用你的数学运算做一个class
class Calculator(object):
def sum(self, x, y):
return x + y
def subtract(self, x, y):
return x - y
#add more operations here
@staticmethod
def start():
while True:
#prompt for input and the operator
这有什么好处是在您检查选择时您可以动态调用 class 方法来大量清理代码
if selection in options:
getattr(options[selection], Calculator)(a, b)
如果你想让我解释更多，我可以完成这个例子。
对于您的循环，您可以添加一个方法来启动操作并继续循环并每次执行更多操作
这是一个基本的class你可以使用我描述的那些方法
class Calculator(object):
loop = None
calculations = 1
current_value = 0
selection = 0
options = {1: 'add', 2: 'subtract', 3: 'multiply', 4: 'divide'}
def __init__(self, loop=True):
self.loop = loop
print 'Welcome to my basic calculator!'
if not self.loop: # dont loop just execute once
self.run()
else:
while True:
self.run()
@staticmethod
def add(x, y):
return x + y
@staticmethod
def subtract(x, y):
return x - y
@staticmethod
def multiply(x, y):
return x * y
@staticmethod
def divide(x, y):
if y != 0: #cant divide by 0
return x / y
@staticmethod
def quit():
exit(0)
def run(self):
if self.calculations == 1:
self.current_value = self.prompt_user_input('please provide a number: ')
self.prompt_operator('Please choose an operator to continue\n1 for addition\n2 for subtraction\n3 for multiplication \n4 for division\n0 to quit\n')
y = self.prompt_user_input('please provide a number: ')
self.current_value = getattr(Calculator, self.options[self.selection])(self.current_value,y)
self.calculations += 1
print 'New value is: ' + str(self.current_value)
def prompt_operator(self, prompt_message):
while True:
self.selection = input(prompt_message)
if self.selection in self.options:
break
elif self.selection == 0:
self.quit()
else:
print("Please choose a valid option")
def prompt_user_input(self, prompt_message):
val = None
while val is None:
try:
val = int(input(prompt_message))
except ValueError:
print "please use a valid integer"
pass
return val
最后，要启动您的计算器，您只需调用它并传递 true 以继续循环或传递 false 以仅进行一次计算
Calculator(loop=True)