我编写了使用python存储历史结果的代码，此代码工作正常。但是我想显示历史和下面的图片一样。在这个程序中只显示历史记录的输出值。但是我需要整个过程的计算历史，而不仅仅是最后的输出值。请帮帮我。
问题图片请参见问题
请看看这个图像，我想把它作为预期的输出。
last_calculation = []
while True:
print("Select operation.")
print("1.Add : + ")
print("2.Subtract : - ")
print("3.Multiply : * ")
print("4.Divide : / ")
print("5.Power : ^ ")
print("6.Remainder: % ")
print("7.Terminate: # ")
print("8.Reset : $ ")
print("8.History : ? ")
def add(x,y):
return x+y
def substract(x,y):
return x-y
def multiply(x,y):
return x*y
def divide(x,y):
return x/y
def power(x,y):
return x**y
def remainder(x,y):
return x%y
def history():
global last_calculation
if last_calculation == []:
print("No past calculations to show")
else:
for i in last_calculation:
print(i) #for single line
# take input from the user
choice = input("Enter choice(+,-,*,/,^,%,#,$,?): ")
print(choice)
if choice == "#":
#program ends here
print("Done. Terminating")
exit()
if choice == "$":
continue
if choice=='?':
history()
continue
try:
a=input("Enter first number: ")
print(a)
if a == "#":
#program ends here
print("Done. Terminating")
exit()
a=float(a)
b=input("Enter second number: ")
print(b)
if b == "#":
#program ends here
print("Done. Terminating")
exit()
b=float(b)
except ValueError:
continue
if choice == "+":
result = add(a, b)
last_calculation.append(result)
print(a, '+', b, '=', add(a,b))
elif choice == "-":
result = substract(a, b)
last_calculation.append(result)
print(a, "-", b, "=", substract(a,b))
elif choice == "*":
result = multiply(a, b)
last_calculation.append(result)
print(a, "*", b, "=", multiply(a,b))
elif choice == "/":
if b == 0.0:
last_calculation.append(result)
print("float division by zero")
print(a, "/", b, "=" " None")
else:
result = divide(a, b)
last_calculation.append(result)
print(a, "/", b, "=", divide(a,b))
elif choice == '^':
result = power(a, b)
last_calculation.append(result)
print(a, "^", b, "=", power(a,b))
elif choice == "%":
result = remainder(a, b)
last_calculation.append(result)
print(a, "%", b, "=", remainder(a,b))
else :
print("Unrecognized operation")
关于如何提高代码的可读性以及问题的根本原因，我有一些小提示。你的代码中有几个部分是可以工作的，但是比它们需要的稍微难以阅读。
-
我不确定每个操作有单独的功能是什么。由于它们都是一行操作，并且都只在代码的另一个地方被调用，因此您现在可以简单地将函数体放在调用它们的地方。
-
与其使用长
if-elif-else结构，不如使用match-case语句。(它们在其他语言中被称为switch-case语句。请看这篇文章 -
使用
While True通常被认为是不好的做法。在你的while循环定义中有一个退出条件更容易读，对于更复杂的项目更容易维护
你的问题的原因是，在你的代码中，last_calculation只被append-ed与你的计算结果，而不是你正在显示的实际字符串。请看下面修改后的代码:
last_calculation = []
while True:
print("Select operation.")
print("1.Add : + ")
print("2.Subtract : - ")
print("3.Multiply : * ")
print("4.Divide : / ")
print("5.Power : ^ ")
print("6.Remainder: % ")
print("7.Terminate: # ")
print("8.Reset : $ ")
print("8.History : ? ")
def add(x,y):
return x+y
def substract(x,y):
return x-y
def multiply(x,y):
return x*y
def divide(x,y):
return x/y
def power(x,y):
return x**y
def remainder(x,y):
return x%y
def history():
global last_calculation
if last_calculation == []:
print("No past calculations to show")
else:
for i in last_calculation:
print(i) #for single line
# take input from the user
choice = input("Enter choice(+,-,*,/,^,%,#,$,?): ")
print(choice)
if choice == "#":
#program ends here
print("Done. Terminating")
exit()
if choice == "$":
continue
if choice=='?':
history()
continue
try:
a=input("Enter first number: ")
print(a)
if a == "#":
#program ends here
print("Done. Terminating")
exit()
a=float(a)
b=input("Enter second number: ")
print(b)
if b == "#":
#program ends here
print("Done. Terminating")
exit()
b=float(b)
except ValueError:
continue
if choice == "+":
resultStr = a + '+' + b + '=' + add(a,b)
last_calculation.append(resultStr)
print(resultStr)
elif choice == "-":
resultStr = a + '-' + b + '=' + substract(a,b)
last_calculation.append(resultStr)
print(resultStr)
elif choice == "*":
resultStr = a + '*' + b + '=' + multiply(a,b)
last_calculation.append(resultStr)
print(resultStr)
elif choice == "/":
if b == 0.0:
resultStr = a + '/' + b + '=' + 'none'
last_calculation.append(resultStr)
print(resultStr)
else:
resultStr = a + '/' + b + '=' + divide(a,b)
last_calculation.append(resultStr)
print(resultStr)
elif choice == '^':
resultStr = a + '^' + b + '=' + power(a,b)
last_calculation.append(resultStr)
print(resultStr)
elif choice == "%":
resultStr = a + '%' + b + '=' + remainder(a,b)
last_calculation.append(resultStr)
print(resultStr)
else :
print("Unrecognized operation")
加上我建议的改动:
last_calculation = []
choice = "Doesn't matter what I put here"
while choice != "#":
print("Select operation.")
print("1.Add : + ")
print("2.Subtract : - ")
print("3.Multiply : * ")
print("4.Divide : / ")
print("5.Power : ^ ")
print("6.Remainder: % ")
print("7.Terminate: # ")
print("8.Reset : $ ")
print("8.History : ? ")
def history():
global last_calculation
if last_calculation == []:
print("No past calculations to show")
else:
for i in last_calculation:
print(i) #for single line
# take input from the user
choice = input("Enter choice(+,-,*,/,^,%,#,$,?): ")
print(choice)
match choice:
case "#":
#program ends here
print("Done. Terminating")
continue
case "$":
continue
case '?':
history()
continue
case _:
try:
a=input("Enter first number: ")
print(a)
if a == "#":
#program ends here
print("Done. Terminating")
continue
a=float(a)
b=input("Enter second number: ")
print(b)
if b == "#":
#program ends here
print("Done. Terminating")
continue
b=float(b)
except ValueError:
continue
match choice:
case "+":
resultStr = a + '+' + b + '=' + (a+b)
last_calculation.append(resultStr)
print(resultStr)
case "-":
resultStr = a + '-' + b + '=' + (a-b)
last_calculation.append(resultStr)
print(resultStr)
case "*":
resultStr = a + '*' + b + '=' + (a*b)
last_calculation.append(resultStr)
print(resultStr)
case "/":
if b == 0.0:
resultStr = a + '/' + b + '=' + 'none'
last_calculation.append(resultStr)
print(resultStr)
else:
resultStr = a + '/' + b + '=' + (a/b)
last_calculation.append(resultStr)
print(resultStr)
case '^':
resultStr = a + '^' + b + '=' + (a**b)
last_calculation.append(resultStr)
print(resultStr)
case "%":
resultStr = a + '%' + b + '=' + (a%b)
last_calculation.append(resultStr)
print(resultStr)
case _:
print("Unrecognized operation")