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"

大写的单词…

str = "this is string example....  wow!!!";
print "str.title() : ", str.title();

@Gary02127评论，下面的解决方案适用于带有撇号的标题

import re

def titlecase(s):
    return re.sub(r"[A-Za-z]+('[A-Za-z]+)?", lambda mo: mo.group(0)[0].upper() + mo.group(0)[1:].lower(), s)

text = "He's an engineer, isn't he? SnippetBucket.com "
print(titlecase(text))

当解决方案简单而安全的时候，为什么你要用连接和for循环来使你的生活复杂化?

只要这样做:

string = "the brown fox"
string[0].upper()+string[1:]

在Python中，您可以使用title()方法将字符串中的每个单词大写:

string = "this is a test string"
capitalized_string = string.title()
print(capitalized_string)

输出:

This Is A Test String

.title()方法不会在所有测试用例中工作，因此将.capitalize()， .replace()和.split()一起使用是将每个单词的第一个字母大写的最佳选择。

def caps(y):

     k=y.split()
     for i in k:
        y=y.replace(i,i.capitalize())
     return y

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"