我刚学python
请允许我来解释一下这个lambda函数
解释不对，请杂砖：－）
x<5 and x or 0
即
if( (x<5)&& (x != 0)) return x;
else return 0;



> On 4/4/06, cry <zyqmail at tom.com> wrote:
> > python，您好！
> >   如何修改一个list里的值呢？比如把下列的值大于5的都变成0。
> >
> > l=[1,2,3,4,5,6,7,8,9]
> > for ll in l:
> >         if ll > 5:
> >                 ll = 0
> >
> > 好象不行，怎么做比较合适呢？受C的影响太严重。:(
> >
> 
> map(lambda x:x<5 and x or 0, l)
> 
> --
> I like python!
> My Blog: http://www.donews.net/limodou
> My Django Site: http://www.djangocn.org
> NewEdit Maillist: http://groups.google.com/group/NewEdit
> 
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在 06-4-4，Jay<wz12 at yeah.net> 写道：
> 我刚学python
> 请允许我来解释一下这个lambda函数
> 解释不对，请杂砖：－）
>
> x<5 and x or 0
> 即
> if( (x<5)&& (x != 0)) return x;
> else return 0;

and or用来模拟三目运算，这样更形象一些：
x < 5? return x: return 0;

Python没有3目运算啊。
----- Original Message ----- 
From: "makeyunbad" <makeyunbad at gmail.com>
To: <python-chinese at lists.python.cn>
Sent: Wednesday, April 05, 2006 9:04 AM
Subject: Re: Re: [python-chinese] about list


>在 06-4-4，Jay<wz12 at yeah.net> 写道：
>> 我刚学python
>> 请允许我来解释一下这个lambda函数
>> 解释不对，请杂砖：－）
>>
>> x<5 and x or 0
>> 即
>> if( (x<5)&& (x != 0)) return x;
>> else return 0;
> 
> and or用来模拟三目运算，这样更形象一些：
> x < 5? return x: return 0;
>


--------------------------------------------------------------------------------


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On 4/5/06, pythonfan <pythonfan at 126.com> wrote:
> Python没有3目运算啊。

2.5中会有了。

--
I like python!
My Blog: http://www.donews.net/limodou
My Django Site: http://www.djangocn.org
NewEdit Maillist: http://groups.google.com/group/NewEdit

不知道2.5的三目写的对不对：)
N = [a>5 if a else 0 for a in I]


On 4/5/06, limodou <limodou at gmail.com> wrote:
>
> On 4/5/06, pythonfan <pythonfan at 126.com> wrote:
> > Python没有3目运算啊。
>
> 2.5中会有了。
>
> --
> I like python!
> My Blog: http://www.donews.net/limodou
> My Django Site: http://www.djangocn.org
> NewEdit Maillist: http://groups.google.com/group/NewEdit
>
> _______________________________________________
> python-chinese
> Post: send python-chinese at lists.python.cn
> Subscribe: send subscribe to python-chinese-request at lists.python.cn
> Unsubscribe: send unsubscribe to  python-chinese-request at lists.python.cn
> Detail Info: http://python.cn/mailman/listinfo/python-chinese
>
>
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On 4/7/06, wangmm <kernellearn at gmail.com> wrote:
>
> 不知道2.5的三目写的对不对：)
> N = [a>5 if a else 0 for a in I]
>

既然不知道建议也不要瞎猜，文档和2.5版都可以下载看啊。看到底是怎么写的。

--
I like python!
My Blog: http://www.donews.net/limodou
My Django Site: http://www.djangocn.org
NewEdit Maillist: http://groups.google.com/group/NewEdit

在 06-4-7，wangmm<kernellearn at gmail.com> 写道：
>
> 不知道2.5的三目写的对不对：)
> N = [a>5 if a else 0 for a in I]

>>> a = 3
>>> a if a < 5 else 0
3
>>> a = 56
>>> a if a < 5 else 0
0
>>> a < 5 if a else 0
False