473,933 Members | 10,805 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Whoa! Do Python and Lisp really have LAMBDA ?

Earlier Ed Schofield (thanks, man) warned us that

flist = []

for i in range(3)
f = lambda x: x + i
flist.append(f)

[f(1) for f in flist]

gives [3, 3, 3]. So much for the principle of minimum surprise!

Doing the same in Lisp (with lists instead of arrays),

(setf flist (loop for i from 0 to 2
collect (lambda (x) (+ x i))))

(loop for f in flist
collect (funcall f 1))

I got (4 4 4).

Lisp has many gotchas, I just wasn't ready for this one.
(Google for "lisp gotchas" - someone posted a comprehensive
list to c.l.l. in 1995. Every Lisper should read it)

I'm sure Haskell does this right. What about Scheme and ML?

Jul 18 '05
10 2036
Q> Scheme doesn't have a for loop either,

It's called DO and it does the right thing.

Juliusz

Jul 18 '05 #11

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

14
2335
by: Quentin | last post by:
Dear Gurus, This is a fairly simple question, but I can't figure out what the answer is. I can easily change my code, but I want to know why I can't do this to further my knowledge of the C++ language (and OO): class a { public: a(){ vm(); }
0
9761
by: Kirt Loki Dankmyer | last post by:
So, I download the latest "stable" tar for perl (5.8.7) and try to compile it on the Solaris 8 (SPARC) box that I administrate. I try all sorts of different switches, but I can't get it to compile. I need it to be compiled with threads. Anyone have any wisdom on how best to do this? Here's a transcript of my latest attempt. It's long; you might want to skip to the bottom, where I try "make" and the fatal errors start happening.
5
1746
by: sparks | last post by:
I am about to pull my hair out on this one. its a class stack with push and pop but one time its trying to find a } at the end of the code the next it says that I need a } after private man I know I am kinda new but this is driving me up the wall .... Should I start over or what. I keep adding things trying to get it to work but no success.
37
3897
by: Ian Rastall | last post by:
I've been working on an online books site for almost four years now, and have been putting smart quotes in each book. This is a major hassle, and I'm beginning to think it's not worth it. Is there a good reason not to use them in the first place? It would certainly be simple to convert back to straight quotes. Ian -- http://sundry.ws/
67
10066
by: lcw1964 | last post by:
This may be in the category of bush-league rudimentary, but I am quite perplexed on this and diligent Googling has not provided me with a clear straight answer--perhaps I don't know how to ask the quesion. I have begun to familiarize myself here with the gcc compiler in a win32 environment, in the form of MinGW using both Dev C++ and MSYS as interfaces. I have recompiled some old math code that uses long double types throughout and...
12
1643
by: Chief | last post by:
Hey I have a CODE that some 1 wrote however he use this line x= (y=4,z=6); ( by the way the output of this line is x=6 , y=4 , z=6 ) i was wondring in what situation i will have to use it? and does it good for? Second thing Can some 1 explain me the way to use the MAX_RAND while
14
2093
by: seralasu | last post by:
Hi, I have refresh problem.When user does refresh or clicks F5 then form variables again posting. It crates same a lot of inserts. I don't know How to solve it.
158
8052
by: pushpakulkar | last post by:
Hi all, Is garbage collection possible in C++. It doesn't come as part of language support. Is there any specific reason for the same due to the way the language is designed. Or it is discouraged due to some specific reason. If someone can give inputs on the same, it will be of great help. Regards, Pushpa
0
10122
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
9954
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
9843
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
1
8199
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
7365
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
6059
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
6267
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4890
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
2
4433
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.