Python在不使用内置函数Python的情况下反转句子中的每个单词，同时保持顺序

Question

不允许使用"Split((、Reverse((、Join((或正则表达式">或任何其他帮助内置python函数

输入如下内容：

"   my name   is scheven     "

输出如下：

"ym eman si nevehcs"

您需要考虑删除输入中的起始空格、中间空格和结束空格

我已经尝试了2次，都失败了，我将分享我解决这个问题的尝试，并可能提出改进的想法

首次尝试：

def reverseString(someString):

#lenOfString = len(someString)-1

emptyList = []

for i in range(len(someString)):
emptyList.append(someString[i])

lenOfString = len(emptyList)-1 
counter = 0
while counter < lenOfString:
if emptyList[counter] == " ":
counter+=1
if emptyList[lenOfString] == " ":
lenOfString-=1
else:
swappedChar = emptyList[counter]
emptyList[counter] = emptyList[lenOfString]
emptyList[lenOfString] = swappedChar
counter+=1
lenOfString-=1

str_contactantion = ""
#emptyList = emptyList[::-1]
#count_spaces_after_letter=0       
for letter in emptyList:
if letter != " ":
str_contactantion+=letter
#str_contactantion+=" "
str_contactantion+=" " 

return str_contactantion

第二次尝试：

def reverse(array, i, j):
emptyList = []
if (j == i ):
return ""
for k in range(i,j):
emptyList.append(array[k])
start = 0
end = len(emptyList) -1
if start > end: # ensure i <= j
start, end =end, start
while start < end:
emptyList[start], emptyList[end] = emptyList[end], emptyList[start]
start += 1
end -= 1
strconcat=""
for selement in emptyList:
strconcat+=selement
return strconcat
def reverseStr(someStr):
start=0
end=0
help=0
strconcat = ""
empty_list = []
for i in range(len(someStr)):
if(someStr[i] == " "):
continue
else:
start = i
j = start
while someStr[j] != " ":
j+=1
end = j
#if(reverse(someStr,start,end) != ""):
empty_list.append(reverse(someStr,start,end))
empty_list.append(" ")
for selement in empty_list:
strconcat += selement
i = end + 1

return strconcat
print(reverseStr("   my name   is scheven     "))

Answer 1

以下操作不需要管理索引：

def reverseString(someString):
result = crnt = ""
for c in someString:
if c != " ":    
crnt = c + crnt    # build the reversed current token
elif crnt:  # you only want to do anything for the first space of many
if result:
result += " "  # append a space first  
result += crnt     # append the current token
crnt = ""          # and reset it
if crnt:
result += " " + crnt
return result
reverseString("   my name   is scheven     ")
# 'ym eman si nevehcs'

Answer 2

试试这个：

def reverseString(someString):
result = ""
word = ""
for i in (someString + " "):
if i == " ":
if word:
result = result + (result and " ") + word
word = ""
else:
word = i + word
return result

然后你可以这样称呼它：

reverseString("   my name   is scheven     ")
# Output: 'ym eman si nevehcs'

Answer 3

试试这个：

string = "   my name   is scheven     "

def reverseString(someString):
result = ''
curr_word = ''
for i in someString:
if i == ' ':
if curr_word:
if result:
result = f'{result} {curr_word}'
else:
result = f'{result}{curr_word}'
curr_word = ''
else:
curr_word = f'{i}{curr_word}'
return result
print(repr(reverseString(string)))

输出：

'ym eman si nevehcs'

---

注意：如果允许使用list.append方法，我建议使用collections.deque，因为它比附加到列表更具性能。但当然，最终您需要将列表合并在一起，并且您提到不允许使用str.join，因此这肯定会带来问题。