當我在代碼中引入產量時，它在 python 中不起作用 (when i introduced yield in code it doesn't work in python)

問題描述

當我在代碼中引入產量時，它在 python 中不起作用 (when i introduced yield in code it doesn't work in python)

在下面的代碼中，在 permute 函數的 if 部分。如果我嘗試使用 yield 它不起作用但是如果我使用 print 它可以工作嗎？有人可以代碼有什麼問題嗎？提前致謝！

def permute(li,l,r):

    if l==r:

        ele = ''.join(li)

        print(ele)

        yield ele

    else:

        for i in range(l,r+1):

        #print(i)
        li[i],li[l]=li[l],li[i]
        permute(li,l+1,r)
        li[i],li[l]=li[l],li[i]

class Solution:

    def find_permutation(self, S):
    # Code here
    s = list(S)
    f = []
    for i in permute(s,0,len(s)‑1):
        print(i)
        f.append(i)
    return f

if name == 'main':

    t=int(input())

    for i in range(t):

        S=input()

        ob = Solution()

        ans = ob.find_permutation(S)

        for i in ans:

            print(i,end=" ")

        print()

</code></pre>





參考解法
方法 1:
 
When performing a recursive call of a function that yields results you need to use yield from before your recursive call.  Otherwise the data yielded by your recursive calls will be ignored:

def permute(li,l,r):
    if l==r:
        ele = ''.join(li)
        yield ele
    else:
        for i in range(l,r+1):
            li[i],li[l]=li[l],li[i]
            yield from permute(li,l+1,r)  #  change here
            li[i],li[l]=li[l],li[i]
(by morning_star007、qouify)
參考文件


when i introduced yield in code it doesn't work in python (CC BY‑SA 2.5/3.0/4.0)