蟒蛇循環回用於循環

Question

我怎麼能執行下面的python 代碼我是新來的Python和越來越困擾的前一個元素，請能有人幫

objects = [............] // Array 
for (i=0; i<objects.length(); i++) { 
    if(readElement(objects[i])){ 
     //do something 
    } else { 
     i--; // so that same object is given in next iteration and readElement cant get true 
    } 
} 

Answer 1

你有沒有使用遞歸考慮？

def func(objects,i): 
    if i == len(objects): 
     return 
    if readElement(objects[i]){ 
     #do something 
     func(objects,i+1) 
    else 
     func(objects,i)--; # so that same object is given in next iteration and readElement cant get true 
    } 
objects = [............] # list 
func(objects,0) 

否則，你可以這樣做（非常不Python的，但只使用作爲您的要求for循環）：

objects = [............] # Array 
func(objects,0) 
M = 10E6 # The maximum number of calls you think is needed to readElement(objects[i]) 
for i in xrange(objects) 
    for j in xrange(M): 
     if readElement(objects[i]): 
      #do something 
      break 

Answer 2

你可以試試這個出

objects = ["ff","gg","hh","ii","jj","kk"] # Array 
count =0 
for i in objects: # (i=0; i<objects.length(); i++) { 
    if i: 
     print i 
    else : 
     print objects[count-1] 
    count =+1 

Answer 3

您的代碼遍歷一系列對象並重復「readElement」，直到它返回「True」，在這種情況下，你稱之爲「做某事」。好了，你可以只寫下來：

for object in objects: 
    while not readElement(object): pass 
    dosomething() 

[編輯：這個答案的第一個版本倒置的邏輯，對不起]

Answer 4

我一直在尋找同樣的事情，但我最後寫一個while循環，並自己管理索引。

這就是說，你的代碼可以用Python實現爲：

objects = [............] # Array 
idx = 0 

while idx < len(objects): 
    if readElement(objects[idx]): 
     # do hacky yet cool stuff 
    elif idx != 0: 
     idx -= 1 # THIS is what you hoped to do inside the for loop 
    else: 
     # some conditions that we haven't thought about how to handle