quote(s, safe='/')

    quote('abc def') -> 'abc%20def'

    Each part of a URL, e.g. the path info, the query, etc., has a

    different set of reserved characters that must be quoted.

    RFC 2396 Uniform Resource Identifiers (URI): Generic Syntax lists

    the following reserved characters.

    reserved    = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "+" |

                  "$" | ","

    Each of these characters is reserved in some component of a URL,

    but not necessarily in all of them.

    By default, the quote function is intended for quoting the path

    section of a URL.  Thus, it will not encode '/'.  This character

    is reserved, but in typical usage the quote function is being

    called on a path where the existing slash characters are used as

    reserved characters.

(END)

quote_plus(s, safe='')

    Quote the query fragment of a URL; replacing ' ' with '+'

In [18]: urllib.quote('abc def')

Out[18]: 'abc%20def'

In [19]: urllib.quote_plus('abc def')

Out[19]: 'abc+def'

urlencode(query, doseq=0)

    Encode a sequence of two-element tuples or dictionary into a URL query string.

    If any values in the query arg are sequences and doseq is true, each

    sequence element is converted to a separate parameter.

    If the query arg is a sequence of two-element tuples, the order of the

    parameters in the output will match the order of parameters in the

    input.

(END)

In [21]: urllib.urlencode({'username':'xixi','passward':'haha'})

Out[21]: 'username=xixi&passward=haha'

In [23]: urllib.urlencode((('username','嘻嘻'),('passward','哈哈')))

Out[23]: 'username=%E5%98%BB%E5%98%BB&passward=%E5%93%88%E5%93%88'