Comments on: 使用帮助？ http://erlang-china.org erlang 中文社区 Tue, 03 Jan 2012 15:49:56 +0000 hourly 1 http://wordpress.org/?v=3.1.1 By: Aneisha http://erlang-china.org/help/comment-page-1#comment-22746 Aneisha Wed, 13 Apr 2011 00:37:22 +0000 http://erlang-china.org/help/#comment-22746 With the bases loaded you struck us out with that aswner! With the bases loaded you struck us out with that aswner!

]]> By: unqiang http://erlang-china.org/help/comment-page-1#comment-21897 unqiang Fri, 11 Mar 2011 13:39:18 +0000 http://erlang-china.org/help/#comment-21897 一个有关抓取网页及2级网页URL的问题 -module(test). -compile(export_all). -import(lists,[reverse/1,reverse/2,map/2]). nano_get_url() -> nano_get_url("www.erlang.org"). nano_get_url(Host) -> {ok,Socket} = gen_tcp:connect(Host, 80, [binary,{packet,0}]), ok = gen_tcp:send(Socket,"GET / HTTP/1.0\r\n\r\n"), receive_data(Socket,[]). receive_data(Socket,SoFar) -> receive {tcp,Socket,Bin} -> receive_data(Socket,[Bin|SoFar]); {tcp_closed,Socket} -> list_to_binary(lists:reverse(SoFar)) end. urls2htmlFile(Urls,File) -> file:write_file(File,urls2html(Urls)). bin2urls(Bin) -> gather_urls(binary_to_list(Bin),[]). urls2html(Urls) -> [h1("Urls"),make_list(Urls)]. h1(Title) -> ["",Title,"\n"]. make_list(L) -> ["\n", map(fun(I) -> ["",I,"\n"] end, L), "\n"]. gather_urls("<a> {Url,T1}=collect_url_body(T,reverse("<a> gather_urls(T,L); gather_urls([],L) -> L. collect_url_body("</a>" ++ T,L) -> {reverse(L,"</a>"),T}; collect_url_body([H|T],L) -> collect_url_body(T,[H|L]); collect_url_body([],_) -> {[],[]}. 从哪儿加函数？ 一个有关抓取网页及2级网页URL的问题

-module(test).
-compile(export_all).
-import(lists,[reverse/1,reverse/2,map/2]).

nano_get_url() ->
nano_get_url(“www.erlang.org”).

nano_get_url(Host) ->
{ok,Socket} = gen_tcp:connect(Host, 80, [binary,{packet,0}]),
ok = gen_tcp:send(Socket,”GET / HTTP/1.0\r\n\r\n”),
receive_data(Socket,[]).

receive_data(Socket,SoFar) ->
receive
{tcp,Socket,Bin} ->
receive_data(Socket,[Bin|SoFar]);
{tcp_closed,Socket} ->
list_to_binary(lists:reverse(SoFar))
end.

urls2htmlFile(Urls,File) ->
file:write_file(File,urls2html(Urls)).

bin2urls(Bin) -> gather_urls(binary_to_list(Bin),[]).

urls2html(Urls) -> [h1("Urls"),make_list(Urls)].

h1(Title) -> ["",Title,"\n"].

make_list(L) ->
["\n",
map(fun(I) -> ["",I,"\n"] end, L),
“\n”].

gather_urls(“
{Url,T1}=collect_url_body(T,reverse(“
gather_urls(T,L);
gather_urls([],L) ->
L.

collect_url_body(“” ++ T,L) -> {reverse(L,”“),T};
collect_url_body([H|T],L) -> collect_url_body(T,[H|L]);
collect_url_body([],_) -> {[],[]}.
从哪儿加函数？

]]> By: 棘手问题高手请帮忙解答 http://erlang-china.org/help/comment-page-1#comment-9867 棘手问题高手请帮忙解答 Fri, 02 Jan 2009 12:55:27 +0000 http://erlang-china.org/help/#comment-9867 The goal of this assignment is to make a distributed fault-tolerant application for a simple computation of prime numbers. (Large prime numbers are user in security algorithms, if you like to know a practical application of this algorithm). A prime number is a number that is only dividable by 1 and itself, i.e. for N to be prime it must hold that for all M between 2 and N-1 the erlang expression N rem M evaluates to something unequal zero. The first few prime numbers are 1,2,3,5,7,11,13,… Write a demonstrator for a fault-tolerant distributed application. A number of computers should be connected in a network, say 1 to N. It is known how they are positioned, i.e., 1 nest to 2, next to 3, … next to N. On each computer you run the same program. This program computes the prime numbers, but it skips numbers that other computers have already analyzed. Thus, if computer 1 starts to compute whether 1 is a prime, then it informs the others, which decide to go on to the next number (2, 3, 4, etc). In the end, all computers print a list of all prime numbers, but never compute a prime number if one of the other computers already took that task. As soon as a computer is disconnected from the network, or the Erlang node that it runs is killed (simulating a crash), then the other computers continue working. When a crashed computer is restarted (or the Erlang node restarted), the program joins the pool and starts doing computations again. The goal of this assignment is to make a distributed fault-tolerant application for a simple
computation of prime numbers. (Large prime numbers are user in security algorithms, if you
like to know a practical application of this algorithm).
A prime number is a number that is only dividable by 1 and itself, i.e. for N to be prime it
must hold that for all M between 2 and N-1 the erlang expression N rem M evaluates to
something unequal zero. The first few prime numbers are 1,2,3,5,7,11,13,…
Write a demonstrator for a fault-tolerant distributed application. A number of computers
should be connected in a network, say 1 to N.
It is known how they are positioned, i.e., 1 nest to 2, next to 3, … next to N.
On each computer you run the same program. This program computes the prime numbers, but
it skips numbers that other computers have already analyzed. Thus, if computer 1 starts to
compute whether 1 is a prime, then it informs the others, which decide to go on to the next
number (2, 3, 4, etc). In the end, all computers print a list of all prime numbers, but never
compute a prime number if one of the other computers already took that task.
As soon as a computer is disconnected from the network, or the Erlang node that it runs is
killed (simulating a crash), then the other computers continue working.
When a crashed computer is restarted (or the Erlang node restarted), the program joins the
pool and starts doing computations again.

]]> By: Erlang-China » Blog Archive » 加了Erlang代码的语法加亮，show一下 http://erlang-china.org/help/comment-page-1#comment-49 Erlang-China » Blog Archive » 加了Erlang代码的语法加亮，show一下 Mon, 16 Apr 2007 13:15:36 +0000 http://erlang-china.org/help/#comment-49 [...] 完整的示例可以参考这里。 [...] [...] 完整的示例可以参考这里。 [...]

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