Python list remove method: how's the implementation? -

-

in java, have client class have "code" attr, , equals method. method equals receives client , compares itself's code attr.

in python, read have __cmp__ method, same java method equals. ok, did that. created class client, "code" attr , method comp verify if code same.

class client():     def __init__(self, code):         self.code = code      def __cmp__(self, obj):         return obj.code == self.code      def __repr__(self):         return str(self.code)

then put 3 client objects in python's list:

bla = [client(1), client(2), client(3)]

then, when try: 

bla.remove(client(3))

the amazing python removes first element (the client code 1).

what doing wrong? searched implementation of list in python's lib files, not easy find.

anyone can help?

http://docs.python.org/reference/datamodel.html#object.__cmp__

__cmp__(self, other)

called comparison operations if rich comparison (see above) not defined. should return negative integer if self < other, 0 if self == other, positive integer if self > other.

basically, should change implementation of __cmp__ be...

def __cmp__(self, obj):     return cmp(obj.code, self.code)

the cmp() builtin function of python designed return values __cmp__ expected return comparing 2 arguments.

there different function in python called __eq__ checks equality, current implementation of __cmp__ better suited.


Comments

Post a Comment

Popular posts from this blog

c++ - How do I get a multi line tooltip in MFC -

-
right now, have tool tip pops when hover on edit box. problem tool tip contains multiple error messages , in 1 long line. need have each error message on own line. error messages contained in cstring new line seperating them. my existing code below. bool ontooltiptext(uint, nmhdr* pnmhdr, lresult* presult) { assert(pnmhdr->code == ttn_needtexta || pnmhdr->code == ttn_needtextw); // need handle both ansi , unicode versions of message tooltiptexta* pttta = (tooltiptexta*)pnmhdr; tooltiptextw* ptttw = (tooltiptextw*)pnmhdr; // tchar szfulltext[256]; cstring strtiptext=_t(""); uint nid = pnmhdr->idfrom; if (pnmhdr->code == ttn_needtexta && (pttta->uflags & ttf_idishwnd) || pnmhdr->code == ttn_needtextw && (ptttw->uflags & ttf_idishwnd)) { // idfrom hwnd of tool nid = ::getdlgctrlid((hwnd)nid); } //m_errprojaccel[ch] contains 1 or more error messages each...
Read more

asp.net - In javascript how to find the height and width -

-
i having .aspx , masterpage page. in masterpage loading aspx page . in aspx page design using generating table structure using code-behind server in javascript how find height , width . regards, kumar if you're looking table height , width, should it var tbl = document.getelementbyid('tbldemo'); alert(tbl.offsetwidth + '\n' + tbl.offsetheight);
Read more

c# - DataTable to EnumerableRowCollection -

-
i have datatable according client requirement can contain invalid date "00/00/1999",null,empty string.(typed datset) when collect them enumerables wish convert of invalid forms empty string. (i.e) enumerablerowcollection<datarow> query = order in _table.asenumerable() select new { orderdate= string.isnullorempty(convert.tostring(order.field<datetime>("orderdate")) || (how check date invalid date) ? string.empty : order.field<datetime>("orderdate") } how check whether date valid date or not? datetime.tryparse...like given current code: datetime date; enumerablerowcollection<datarow> query = order in _table.asenumerable() select new { orderdate= string.isnullorempty(convert.tostring(order.field<datetime>("orderdate")) || !datetime.tryparse(convert.tostring(order.field<datetime...
Read more