我认为while循环是“goto_Statement”的替代。因为3.6之后，goto循环不再工作了。我还写了一个while循环的例子。

str1 = "stop"
while str1 == "back":
    var1 = int(input(" Enter Ist Number: "))
    var2 = int(input(" Enter 2nd Number: "))
    var3 = print("""  What is your next operation
                      For Addition   Press And Enter : 'A'
                      For Muliplt    Press And Enter : 'M'
                      For Division   Press And Enter : 'D'
                      For Subtaction Press And Enter : 'S' """)

    var4 = str(input("For operation press any number : "))
    if(var1 == 45) and (var2 == 3):
        print("555")
    elif(var1 == 56) and (var2 == 9):
        print("77")
    elif(var1 == 56) and (var2 == 6):
        print("4")
    else:
        if(var4 == "A" or "a"):
            print(var1 + var2)
        if(var4 == "M" or "m"):
            print(var1 * var2)
        if(var4 == "D" or "d"):
            print(var1 / var2)
        if(var4 == "S" or "s"):
            print(var1 - var2)

    print("if you want to continue then type  'stop'")

    str1 = input()
print("Strt again")    

通过一些工作，在python中添加类似“goto”的语句在技术上是可行的。我们将使用"dis"和"new"模块，这两个模块对于扫描和修改python字节代码都非常有用。

实现背后的主要思想是首先将代码块标记为使用“goto”和“label”语句。一个特殊的“@goto”装饰器将用于标记“goto”函数。然后，我们扫描这两个语句的代码，并对底层字节代码应用必要的修改。这一切都发生在源代码编译时。

import dis, new

def goto(fn):
    """
    A function decorator to add the goto command for a function.

        Specify labels like so:
        label .foo

        Goto labels like so:
        goto .foo

        Note: you can write a goto statement before the correspnding label statement
    """
    labels = {}
    gotos = {}
    globalName = None
    index = 0
    end = len(fn.func_code.co_code)
    i = 0

    # scan through the byte codes to find the labels and gotos
    while i < end:
        op = ord(fn.func_code.co_code[i])
        i += 1
        name = dis.opname[op]

        if op > dis.HAVE_ARGUMENT:
            b1 = ord(fn.func_code.co_code[i])
            b2 = ord(fn.func_code.co_code[i+1])
            num = b2 * 256 + b1

            if name == 'LOAD_GLOBAL':
                globalName = fn.func_code.co_names[num]
                index = i - 1
                i += 2
                continue

            if name == 'LOAD_ATTR':
                if globalName == 'label':
                    labels[fn.func_code.co_names[num]] = index
                elif globalName == 'goto':
                    gotos[fn.func_code.co_names[num]] = index

            name = None
            i += 2

    # no-op the labels
    ilist = list(fn.func_code.co_code)
    for label,index in labels.items():
        ilist[index:index+7] = [chr(dis.opmap['NOP'])]*7

    # change gotos to jumps
    for label,index in gotos.items():
        if label not in labels:
            raise Exception("Missing label: %s"%label)

        target = labels[label] + 7   # skip NOPs
        ilist[index] = chr(dis.opmap['JUMP_ABSOLUTE'])
        ilist[index + 1] = chr(target & 255)
        ilist[index + 2] = chr(target >> 8)

    # create new function from existing function
    c = fn.func_code
    newcode = new.code(c.co_argcount,
                       c.co_nlocals,
                       c.co_stacksize,
                       c.co_flags,
                       ''.join(ilist),
                       c.co_consts,
                       c.co_names,
                       c.co_varnames,
                       c.co_filename,
                       c.co_name,
                       c.co_firstlineno,
                       c.co_lnotab)
    newfn = new.function(newcode,fn.func_globals)
    return newfn


if __name__ == '__main__':

    @goto
    def test1():
        print 'Hello' 

        goto .the_end
        print 'world'

        label .the_end
        print 'the end'

    test1()

希望这回答了问题。

我想要同样的答案，我不想使用goto。所以我使用了下面的例子(来自learnpythonthehardway)

def sample():
    print "This room is full of gold how much do you want?"
    choice = raw_input("> ")
    how_much = int(choice)
    if "0" in choice or "1" in choice:
        check(how_much)
    else:
        print "Enter a number with 0 or 1"
        sample()

def check(n):
    if n < 150:
        print "You are not greedy, you win"
        exit(0)
    else:
        print "You are nuts!"
        exit(0)

虽然在Python中没有任何等同于goto/label的代码，但您仍然可以使用循环来获得goto/label的这种功能。

让我们以下面所示的代码示例为例，其中goto/label可以在python以外的任意语言中使用。

String str1 = 'BACK'

label1:
    print('Hello, this program contains goto code\n')
    print('Now type BACK if you want the program to go back to the above line of code. Or press the ENTER key if you want the program to continue with further lines of code')
    str1 = input()

if str1 == 'BACK'
    {
        GoTo label1
    }
print('Program will continue\nBla bla bla...\nBla bla bla...\nBla bla bla...')

现在，通过使用下面所示的while循环，可以在python中实现上述代码示例的相同功能。

str1 = 'BACK'

while str1 == 'BACK':
        print('Hello, this is a python program containing python equivalent code for goto code\n')
        print('Now type BACK if you want the program to go back to the above line of code. Or press the ENTER key if you want the program to continue with further lines of code')
        str1 = input()
print('Program will continue\nBla bla bla...\nBla bla bla...\nBla bla bla...')

你可以使用用户定义异常来模拟goto

例子:

class goto1(Exception):
    pass   
class goto2(Exception):
    pass   
class goto3(Exception):
    pass   


def loop():
    print 'start'
    num = input()
    try:
        if num<=0:
            raise goto1
        elif num<=2:
            raise goto2
        elif num<=4:
            raise goto3
        elif num<=6:
            raise goto1
        else:
            print 'end'
            return 0
    except goto1 as e:
        print 'goto1'
        loop()
    except goto2 as e:
        print 'goto2'
        loop()
    except goto3 as e:
        print 'goto3'
        loop()

对于一个向前的后藤，你可以添加:

while True:
  if some condition:
    break
  #... extra code
  break # force code to exit. Needed at end of while loop
#... continues here

但这只适用于简单的场景(即嵌套这些会让你陷入混乱)