試圖設置一個字符在一個特定位置的字符到另一個字符

Question

我想嘗試這樣做，而不使用索引。

def SSet(s, i, c): 
#A copy of the string 's' with the character in position 'i' 
#set to character 'c' 
count = -1 
for item in s: 
    if count >= i: 
     count += 1 
    if count == i: 
     item += c 
print(s) 

print(SSet("Late", 3, "o")) 

在這個例子中，遲到應該改爲Lato。

謝謝。

Answer 1

您沒有累加器來保存輸出，並且計數器上的邏輯關閉。以下循環遍歷字符串並將字符連接到輸出，除非字符索引是在給定字符的哪一點給出的索引。

def SSet(s, i, c): 
    """A copy of the string 's' with the character in position 'i' set to character 'c'""" 
    res = "" 
    count = -1 
    for item in s: 
     count += 1 
     if count == i: 
      res += c 
     else: 
      res += item 
    return res 

print(SSet("Late", 3, "o")) 

打印

Lato 

這可以羅列其去除反寫更好：

def SSet(s, i, c): 
    """A copy of the string 's' with the character in position 'i' set to character 'c'""" 
    res = "" 
    for index, item in enumerate(s): 
     if index == i: 
      res += c 
     else: 
      res += item 
    return res 

它也通過附加字符的列表，然後加入進行得更快他們在最後：

def SSet(s, i, c): 
    """A copy of the string 's' with the character in position 'i' set to character 'c'""" 
    res = [] 
    for index, item in enumerate(s): 
     if index == i: 
      res.append(c) 
     else: 
      res.append(item) 
    return ''.join(res) 

它也沒有提出的對，但這裏是如何與切片做到這一點：

def SSet(s, i, c): 
    """A copy of the string 's' with the character in position 'i' set to character 'c'""" 
    return s[:i]+c+s[i+1:] 

Answer 2

def SSet(s, i, c): 
#A copy of the string 's' with the character in position 'i' 
#set to character 'c' 
    count = 0 
    strNew="" 
    for item in s: 
     if count == i: 
      strNew=strNew+c 
     else: 
      strNew=strNew+item 
     count=count+1 

    return strNew 

print(SSet("Late", 3, "o"))