我一般是python或编码的新手，而我的while循环遇到了问题。我想指出的是，while循环仅在变量“ loop” = True时有效
loop = True #Makes the asking sequence work
def loop_again(): #Makes the program ask if you want to continue
loop_again = str(input("Do you want to do this again? Yes or No: "))
if loop_again == "Yes":
loop = True
elif loop_again == "No":
loop = False
else:
print("Please answer yes or no: ")
loop_again
当程序询问我是否要再次执行此操作时，当我写“ No”时，即使我键入“ No”时变量“ loop”被假定为false，它仍会循环执行序列停止循环。
完整代码（在代码底部的while循环中）：
#Solving for the area in a shape automatically
import math
loop = True #Makes the asking sequence work
def loop_again(): #Makes the program ask if you want to continue
loop_again = str(input("Do you want to do this again? Yes or No: "))
if loop_again == "Yes":
loop = True
elif loop_again == "No":
loop = False
else:
print("Please answer yes or no: ")
loop_again
def sqr_area(): #Asking sequence for the area of the square
if choose == "Square":
a = float(input("Input the length of the side here: "))
print(a ** 2)
loop_again()
def rec_area(): #Asking sequence for the area of the rectangle
if choose == "Rectangle":
a = float(input("Input the length of the long sides here: "))
b = float(input("Input the length of the short sides here: "))
print(a * b)
loop_again()
def tri_area(): #Asking sequence for the area of the triangle
a = float(input("Input the length of the side: "))
b = float(input("Input the length of the height: "))
print((a * b) / 2)
loop_again()
def cir_area(): #Asking sequence for the area of the circle
r = float(input("Length of the radius: "))
print((r ** 2) * math.pi)
loop_again()
while loop == True: #While loop, asking sequence
choose = str(input("Input what shape that you want to figure out the area of here: "))
if choose == "Square":
sqr_area()
elif choose == "Rectangle":
rec_area()
elif choose == "Triangle":
tri_area()
elif choose == "Circle":
cir_area()
else:
print("Invalid shape, Input one of these shapes: Square, Rectangle, Triangle, Circle")
choose
谢谢！
答案 0 :(得分：2)
在应该使用循环时不要使用递归，并且SELECT
t1.col1,
t1.col2,
t1.col3,
t2.score
FROM yourTable t1
INNER JOIN
(
SELECT MIN(col1, col2) AS col1, MAX(col1, col2) AS col2, AVG(score) AS score
FROM yourTable
GROUP BY MIN(col1, col2) AS col1, MAX(col1, col2)
) t2
ON MIN(t1.col1, t1.col2) = t2.col1 AND
MAX(t1.col1, t1.col2) = t2.col2;
应该返回一个值，而不是全局设置loop_again。
loopimport math
# Returns true once the input is Yes or false once the input is No
def loop_again():
while True:
response = str(input("Do you want to do this again? Yes or No: "))
if response == "Yes":
return True
elif response == "No":
return False
else:
print("Please answer yes or no: ")
函数返回之后，而不是在每个函数内部，应该在 之后调用 loop_again。功能不需要了解或关心
关于*_area的值；仅在打算调用它们时才调用它们。
choose最终循环可以无限期地运行，直到# Print the area of a square
def sqr_area():
a = float(input("Input the length of the side here: "))
print(a ** 2)
# Print the area of a rectangle
def rec_area():
a = float(input("Input the length of the long sides here: "))
b = float(input("Input the length of the short sides here: "))
print(a * b)
# Print the area of a triangle
def tri_area():
a = float(input("Input the length of the side: "))
b = float(input("Input the length of the height: "))
print((a * b) / 2)
# Print the area of a circle
def cir_area():
r = float(input("Length of the radius: "))
print((r ** 2) * math.pi)
返回loop_again。
True答案 1 :(得分：1)
您必须在loop_again()函数的开头添加以下内容：
global loop
否则，该变量被视为 local ，并且不会对位于外部范围内的 other loop变量产生任何影响。
答案 2 :(得分：0)
这是一个上下文变量问题。 loop中的loop_again()变量和while循环中的变量是不同的。
在python中，函数内部的每个变量都是局部变量，除非它是一个自变量，或者如果您在函数的主函数和内部使用global variable。
因此将其设为全局或传递并在函数内部返回
#Solving for the area in a shape automatically
import math
global loop
loop = True #Makes the asking sequence work
def loop_again(): #Makes the program ask if you want to continue
global loop
loop_again = str(input("Do you want to do this again? Yes or No: "))
if loop_again == "Yes":
loop = True
elif loop_again == "No":
loop = False
else:
print("Please answer yes or no: ")
loop_again
def sqr_area(): #Asking sequence for the area of the square
if choose == "Square":
a = float(input("Input the length of the side here: "))
print(a ** 2)
loop_again()
def rec_area(): #Asking sequence for the area of the rectangle
if choose == "Rectangle":
a = float(input("Input the length of the long sides here: "))
b = float(input("Input the length of the short sides here: "))
print(a * b)
loop_again()
def tri_area(): #Asking sequence for the area of the triangle
a = float(input("Input the length of the side: "))
b = float(input("Input the length of the height: "))
print((a * b) / 2)
loop_again()
def cir_area(): #Asking sequence for the area of the circle
r = float(input("Length of the radius: "))
print((r ** 2) * math.pi)
loop_again()
while loop == True: #While loop, asking sequence
global loop
choose = str(input("Input what shape that you want to figure out the area of here: "))
if choose == "Square":
sqr_area()
elif choose == "Rectangle":
rec_area()
elif choose == "Triangle":
tri_area()
elif choose == "Circle":
cir_area()
else:
print("Invalid shape, Input one of these shapes: Square, Rectangle, Triangle, Circle")
choose
您需要在每个函数中都说循环是全局函数，否则python会将其解释为局部变量。
另一种方式是：
import math
loop = True #Makes the asking sequence work
def loop_again(loop ): #Makes the program ask if you want to continue
loop_again = str(input("Do you want to do this again? Yes or No: "))
if loop_again == "Yes":
loop = True
elif loop_again == "No":
loop = False
else:
print("Please answer yes or no: ")
loop_again
return loop
def sqr_area(loop): #Asking sequence for the area of the square
if choose == "Square":
a = float(input("Input the length of the side here: "))
print(a ** 2)
loop = loop_again()
return loop
def rec_area(loop): #Asking sequence for the area of the rectangle
if choose == "Rectangle":
a = float(input("Input the length of the long sides here: "))
b = float(input("Input the length of the short sides here: "))
print(a * b)
loop = loop_again(loop)
return loop
def tri_area(loop): #Asking sequence for the area of the triangle
a = float(input("Input the length of the side: "))
b = float(input("Input the length of the height: "))
print((a * b) / 2)
loop = loop_again()
def cir_area(loop): #Asking sequence for the area of the circle
r = float(input("Length of the radius: "))
print((r ** 2) * math.pi)
loop = loop_again()
while loop == True: #While loop, asking sequence
choose = str(input("Input what shape that you want to figure out the area of here: "))
if choose == "Square":
loop = sqr_area(loop )
elif choose == "Rectangle":
loop = rec_area(loop )
elif choose == "Triangle":
loop = tri_area(loop )
elif choose == "Circle":
loop = cir_area(loop )
else:
print("Invalid shape, Input one of these shapes: Square, Rectangle, Triangle, Circle")
choose```