Wednesday, April 6, 2011

Delete Chars in Python

does anybody know how to delete all characters behind a specific character??

like this:

http://google.com/translate_t

into

http://google.com
From stackoverflow
  • str="http://google.com/translate_t"
    shortened=str[0:str.rfind("/")]
    

    Should do it. str[a:b] returns a substring in python. And rfind is used to find the index of a character sequence, starting at the end of the string.

    Kamil Kisiel : SilentGhost's rpartition version is more clear, IMO.
    ΤΖΩΤΖΙΟΥ : Also, if there is no "/" in the string, this returns the initial string shortened by one character.
    Dennis Kempin : ah, you're right. That snippet was a bit naive.
  • If you know the position of the character then you can use the slice syntax to to create a new string:

    In [2]: s1 = "abc123"
    In [3]: s2 = s1[:3]
    In [4]: print s2
    abc
    

    To find the position you can use the find() or index() methods of strings. The split() and partition() methods may be useful, too. Those methods are documented in the Python docs for sequences.

    To remove a part of a string is imposible because strings are immutable.

    If you want to process URLs then you should definitely use the urlparse library. It lets you split an URL into its parts. If you just want remove a part of the file path then you will have to do that still by yourself.

  • if you're asking about an abstract string and not url you could go with:

    >>> astring ="http://google.com/translate_t"
    >>> astring.rpartition('/')[0]
    http://google.com
    
    J.F. Sebastian : `string` is a builtin module in Python therefore it is bad to use it as a variable name.
    SilentGhost : @jfs: it's a standard library module. it may or may not clash with certain variable names.
    Carl Meyer : Note the rpartition method only exists in Python 2.5+, for earlier versions you'd need to use rsplit('/', 1).
    Wallacoloo : @Carl Meyer actually `rsplit("/", 1)[0]`
  • For urls, using urlparse:

    >>> import urlparse
    >>> parts = urlparse.urlsplit('http://google.com/path/to/resource?query=spam#anchor')
    >>> parts
    ('http', 'google.com', '/path/to/resource', 'query=spam', 'anchor')
    >>> urlparse.urlunsplit((parts[0], parts[1], '', '', ''))
    'http://google.com'
    

    For arbitrary strings, using re:

    >>> import re
    >>> re.split(r'\b/\b', 'http://google.com/path/to/resource', 1)
    ['http://google.com', 'path/to/resource']
    

0 comments:

Post a Comment