Task 1 : 首字母大写

import re     #python 正则表达式包：res='hello world's=re.sub(r"\w+",lambda match:match.group(0).capitalize(),s)

赏析：

re.sub，实现正则的替换。

re.sub(pattern, repl, string, count=0, flags=0)Return the string obtained by replacing the leftmost non-overlapping occurrences of pattern in string by the replacement repl. If the pattern isn’t found, string is returned unchanged. repl can be a string or a function; if it is a string, any backslash escapes in it are processed. That is, \n is converted to a single newline character, \r is converted to a carriage return, and so forth. Unknown escapes such as \j are left alone. Backreferences, such as \6, are replaced with the substring matched by group 6 in the pattern. For example:>>>>>> re.sub(r'def\s+([a-zA-Z_][a-zA-Z_0-9]*)\s*\(\s*\):',...        r'static PyObject*\npy_\1(void)\n{
    ',...        'def myfunc():')'static PyObject*\npy_myfunc(void)\n{
    'If repl is a function, it is called for every non-overlapping occurrence of pattern. The function takes a single match object argument, and returns the replacement string. For example:>>>>>> def dashrepl(matchobj):...     if matchobj.group(0) == '-': return ' '...     else: return '-'>>> re.sub('-{1,2}', dashrepl, 'pro----gram-files')'pro--gram files'>>> re.sub(r'\sAND\s', ' & ', 'Baked Beans And Spam', flags=re.IGNORECASE)'Baked Beans & Spam'The pattern may be a string or an RE object.The optional argument count is the maximum number of pattern occurrences to be replaced; count must be a non-negative integer. If omitted or zero, all occurrences will be replaced. Empty matches for the pattern are replaced only when not adjacent to a previous match, so sub('x*', '-', 'abc') returns '-a-b-c-'.In string-type repl arguments, in addition to the character escapes and backreferences described above, \g
     
       will use the substring matched by the group named name, as defined by the (?P
      
       ...) syntax. \g
       
         uses the corresponding group number; \g<2> is therefore equivalent to \2, but isn’t ambiguous in a replacement such as \g<2>0. \20 would be interpreted as a reference to group 20, not a reference to group 2 followed by the literal character '0'. The backreference \g<0> substitutes in the entire substring matched by the RE.Changed in version 2.7: Added the optional flags argument.
       
      
     

Pattern  :  r"w+"表示匹配数字和字母下划线的多个字符。

repl  : lambda match:match.group(0).capitalize()表示首字母大写。