尽管所有的答案都是令人满意的，但我将尝试涵盖两个额外的情况以及所有前面的情况。

如果空间不均匀，你想保持不变

string = hello    world i  am    here.

如果所有的字符串不是从字母开始

string = 1 w 2 r 3g

在这里你可以使用这个:

def solve(s):
    a = s.split(' ')
    for i in range(len(a)):
        a[i]= a[i].capitalize()
    return ' '.join(a)

这将给你:

output = Hello    World I  Am    Here
output = 1 W 2 R 3g

如果str.title()对您不起作用，请自己大写。

将字符串拆分为单词列表 每个单词的第一个字母大写 把单词连接成一个字符串

一行程序:

>>> ' '.join([s[0].upper() + s[1:] for s in "they're bill's friends from the UK".split(' ')])
"They're Bill's Friends From The UK"

明显的例子:

input = "they're bill's friends from the UK"
words = input.split(' ')
capitalized_words = []
for word in words:
    title_case_word = word[0].upper() + word[1:]
    capitalized_words.append(title_case_word)
output = ' '.join(capitalized_words)

如果你只想知道第一个字母:

>>> 'hello world'.capitalize()
'Hello world'

但是每个单词都要大写:

>>> 'hello world'.title()
'Hello World'

.title()方法不能很好地工作，

>>> "they're bill's friends from the UK".title()
"They'Re Bill'S Friends From The Uk"

试试string.capwords()方法，

import string
string.capwords("they're bill's friends from the UK")
>>>"They're Bill's Friends From The Uk"

来自Python capwords文档:

使用str.split()将参数拆分为单词，使用str.capitalize()将每个单词大写，并使用str.join()连接大写的单词。如果可选的第二个参数sep不存在或为None，则空白字符的运行将被单个空格替换，并且前导和尾部的空白将被删除，否则sep用于分隔和连接单词。

对你的问题最简单的解决方法，在我的情况下是有效的:

import string
def solve(s):
    return string.capwords(s,' ') 
    
s=input()
res=solve(s)
print(res)

这里总结了不同的方法，以及一些需要注意的陷阱

它们将适用于所有这些输入:

""           => ""       
"a b c"      => "A B C"             
"foO baR"    => "FoO BaR"      
"foo    bar" => "Foo    Bar"   
"foo's bar"  => "Foo's Bar"    
"foo's1bar"  => "Foo's1bar"    
"foo 1bar"   => "Foo 1bar"     

Splitting the sentence into words and capitalizing the first letter then join it back together: # Be careful with multiple spaces, and empty strings # for empty words w[0] would cause an index error, # but with w[:1] we get an empty string as desired def cap_sentence(s): return ' '.join(w[:1].upper() + w[1:] for w in s.split(' ')) Without splitting the string, checking blank spaces to find the start of a word def cap_sentence(s): return ''.join( (c.upper() if i == 0 or s[i-1] == ' ' else c) for i, c in enumerate(s) ) Or using generators: # Iterate through each of the characters in the string # and capitalize the first char and any char after a blank space from itertools import chain def cap_sentence(s): return ''.join( (c.upper() if prev == ' ' else c) for c, prev in zip(s, chain(' ', s)) ) Using regular expressions, from steveha's answer: # match the beginning of the string or a space, followed by a non-space import re def cap_sentence(s): return re.sub("(^|\s)(\S)", lambda m: m.group(1) + m.group(2).upper(), s)

现在，这些是其他一些被发布的答案，如果我们将一个单词定义为句子的开头或空格后的任何东西，输入就不会像预期的那样工作:

.title () 返回s.title () #不需要的输出: "foO baR" => "foO baR" "foo's bar" => "foo's bar" "foo's1bar" => "foo's1bar" "foo 1bar" => "foo 1bar"

.capitalize()或.capwords() 返回' '.join(w.r esize () for s.split()中的w) #或 进口的字符串 返回string.capwords(年代) #不需要的输出: "foO baR" => "foO baR" "foo bar" => "foo bar" 使用' '作为分割将修复第二个输出，但不能修复第一个输出 返回' '.join(w.r esize () for w in s.s split(' ')) #或 进口的字符串 返回字符串。大写字符(s， ' ') #不需要的输出: "foO baR" => "foO baR"

.upper () 注意使用多个空格，这可以通过使用' '进行分割来修复(如答案顶部所示) 返回' ' . join (w [0] .upper () + w (1:) w s.split ()) #不需要的输出: "foo bar" => "foo bar"