golden armor

from http://wiki.asp.net/page.aspx/721/using-responseredirect-and-responseend-in-trycatch-block/

In ASP.NET if you are using Response.End - Used for terminating page execution or Response.Redirect - used for redirecting page to some other page, and you are including these statements in TRY... CATCH block here is what you need to remember.

Problem:

When Response.Redirect or Response.End is written in TRY block, code in catch block is executed.

Reason:

ASP.NET executes these 2 methods on Response object by throwing ThreadAbort Exception. When written in simple Try...Catch block this results in Catch block catching this exception and processing code written in catch block. This causes unwanted code execution e.g. error logging or genric error display code which is generally written in Catch block.

Solution:

You need to handle ThreadAbort exception separately and do nothing if it is thrown. Refer following code patch:

try
{
// Your actual code
Response.End();
}
catch (ThreadAbortException exc)
{
// This should be first catch block i.e. before generic Exception
// This Catch block is to absorb exception thrown by Response.End
}
catch (Exception exc)
{
// Write actual error handling code here
}

题目：
给定一个十进制正整数 N，写下从1 开始，到 N的所有整数，然后数一下其中出现的所有“1”的个数。
例如：
N= 2，写下1，2。这样只出现了 1 个“1”。
N= 12，我们会写下1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12。这样，1
的个数是5。
问题是：
写一个函数f （N） ， 返回1到N之间出现的“1”的个数,比如f （12）
=5。

书里面用数学归纳法列出公式，进行计算。
我没想那么多，直接用递归解决，看着没人家清楚，不过我可以说俺的代码简洁:0

def sum1s(C) :
    iLen = len(str(C))
    if iLen == 1 :
        return 1
    iFirst = C / (10 ** ( iLen - 1 ))
    if iFirst != 1 :
        return iFirst * sum1s(10**(iLen-1)-1) + 10 ** (iLen-1) + sum1s(C-iFirst*(10**(iLen-1)))
    else :
        return iFirst * sum1s(10**(iLen-1)-1) + C-iFirst*(10**(iLen-1)) + sum1s(C-iFirst*(10**(iLen-1))) + 1

if __name__ == "__main__" :
    iResult = sum1s(9999999999)
    print "result is %d" % iResult

stdlib中不支持多List的zip函数，最多支持3个List，以下是我的尝试，支持锯齿List组
参数形式为L = [[L11,L12,L13,...],[L21,L22,L23,...],...[Ln1,Ln2,Ln3,...]]

-module(myzip).
%%-compile(export_all).
-export([zip/1,zip_longest/1]).

%%L = [[L11,L12,L13,...],[L21,L22,L23,...],...[Ln1,Ln2,Ln3,...]]
zip(L) ->
zip_tr(L).

zip_tr(L) ->
IniAcc0 = array:to_list(array:new(lists:min([length(I) || I <-L ]),{default,[]})),
Results = [lists:reverse(I) || I <- lists:foldl(fun zipfunc/2, IniAcc0, L )],
%%io:format("~p~n",[Results]),
Results.

zipfunc(Elem, AccIn) ->
%%io:format("~p~n",[AccIn]),
zipfunc_tr(Elem, AccIn, 1, length(AccIn)).

zipfunc_tr(_,AccIn,_Index,0) ->
AccIn;
zipfunc_tr([H|T], AccIn, Index, Count) ->
%%io:format("~p~n",[element(1,lists:split(Index-1,AccIn)) ++
%% [[H|lists:nth(Index,AccIn)]] ++ element(2,lists:split(Index, AccIn))]),
zipfunc_tr(T, element(1,lists:split(Index-1,AccIn)) ++
[[H|lists:nth(Index,AccIn)]] ++ element(2,lists:split(Index, AccIn)), Index+1, Count-1).

zip_longest(L) ->
zip_longest_tr(L).

zip_longest_tr(L) ->
IniAcc0 = array:to_list(array:new(lists:max([length(I) || I <-L ]),{default,[]})),
Results = [lists:reverse(I) || I <- lists:foldl(fun zipfunc_longest/2, IniAcc0, L )],
%%io:format("~p~n",[Results]),
Results.

zipfunc_longest(Elem, AccIn) ->
zipfunc_longest_tr(Elem, AccIn, 1, length(AccIn)).

zipfunc_longest_tr(_,AccIn,_Index,0) ->
AccIn;
zipfunc_longest_tr([],AccIn,Index,Count) ->
zipfunc_longest_tr([],element(1,lists:split(Index-1,AccIn)) ++
[[undefined|lists:nth(Index,AccIn)]] ++ element(2,lists:split(Index,AccIn)), Index+1, Count-1);
zipfunc_longest_tr([H|T], AccIn, Index, Count) ->
zipfunc_longest_tr(T, element(1,lists:split(Index-1,AccIn)) ++
[[H|lists:nth(Index,AccIn)]] ++ element(2,lists:split(Index,AccIn)), Index+1, Count-1).

输出：
4> L=[[l11,l12,l13],[l21,l22,l23,l24,l25],[l31,l32,l33,l34]].
[[l11,l12,l13],[l21,l22,l23,l24,l25],[l31,l32,l33,l34]]
5> myzip:zip_longest(L).
[[l11,l21,l31],
[l12,l22,l32],
[l13,l23,l33],
[undefined,l24,l34],
[undefined,l25,undefined]]
6> myzip:zip(L).
[[l11,l21,l31],[l12,l22,l32],[l13,l23,l33]]

Ajax的处理都是异步的，所以想实现文件下载这种同步的操作，就比较捉襟见肘。
不过google了一下，找到了一个方法，当然不是完美
主旨就是提交一个request，在server端将文件生成好，然后返回文件名，
client端则在js中隐藏一个frame，将frame的src指向生成的文件（根据返回的文件名）

client:
Ext.Ajax.request({
url: '/csvoutput/',
success: function(r, o) {
obj = Ext.util.JSON.decode(r.responseText);
try {
Ext.destroy(Ext.get('downloadIframe'));
}
catch(e) {}
Ext.DomHelper.append(document.body, {
tag: 'iframe',
id:'downloadIframe',
frameBorder: 0,
width: 0,
height: 0,
css: 'display:none;visibility:hidden;height:0px;',
src: obj.filename
});
},
failure: function(r, o){
},
headers: {
'my-header': 'csvoutput'
},
params: { }
});

server:(django)
result = {}
result['filename'] = filename
result['success'] = True
return HttpResponse(simplejson.dumps(result), mimetype='text/javascript')

用django尝试写了一个简单的业务类site，真是一波三折。
djangoproject上的doc中规中矩，到挑不出毛病，但是碰到
一些个性化问题，就捉襟见肘啦

1，虽然django1.0已经提供了formwizard了，应该很好用，
可惜我的要求比较变态，还是不能胜任，所以索性就用hiddenfield
来一个一个form传下去(formwizard后台其实也是这么做的）

2，ChoiceField定义的时候，并不能动态的获得显示记录集，这个时候
可以重载form或者ChoiceField构造函数，来为以后的动态设定留下钩子。
例子如下：

class XXXXXXForm( forms.Form ) :
    def __init__( self, myqs, *args, **kwargs ) :
        self.myqs = myqs
        super(XXXXXXForm, self).__init__(*args, **kwargs)
        list_xxxxx = forms.ModelChoiceField( queryset=None,
                                           widget=forms.RadioSelect(), empty_label=None, required=False )
        hidden_xxx_name    = forms.CharField( max_length = 80, widget=forms.HiddenInput() ) 
        hidden_xxxxxx_name = forms.CharField( max_length = 40, widget=forms.HiddenInput() ) 

    def populate( self ) :
        self.fields['list_xxxxx'].queryset = XXXXXXX.objects.filter( xxxxxx_type__code=self.myqs )

声明变量的时候，不要忘了紧接着调用populate
default = {'hidden_xxx_name':xxx, 'hidden_xxxxxx_name': xxxxxx}
form3 = DepartStationListForm( qs, default )
form3.populate()