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• Permuting a binary tree without the use of lists

  - by Banang

  I need to find an algorithm for generating every possible permutation of a binary tree, and need to do so without using lists (this is because the tree itself carries semantics and restraints that cannot be translated into lists). I've found an algorithm that works for trees with the height of three or less, but whenever I get to greater hights, I loose one set of possible permutations per height added. Each node carries information about its original state, so that one node can determine if all possible permutations have been tried for that node. Also, the node carries information on weather or not it's been 'swapped', i.e. if it has seen all possible permutations of it's subtree. The tree is left-centered, meaning that the right node should always (except in some cases that I don't need to cover for this algorithm) be a leaf node, while the left node is always either a leaf or a branch. The algorithm I'm using at the moment can be described sort of like this: if the left child node has been swapped swap my right node with the left child nodes right node set the left child node as 'unswapped' if the current node is back to its original state swap my right node with the lowest left nodes' right node swap the lowest left nodes two childnodes set my left node as 'unswapped' set my left chilnode to use this as it's original state set this node as swapped return null return this; else if the left child has not been swapped if the result of trying to permute left child is null return the permutation of this node else return the permutation of the left child node if this node has a left node and a right node that are both leaves swap them set this node to be 'swapped' The desired behaviour of the algoritm would be something like this: branch / | branch 3 / | branch 2 / | 0 1 branch / | branch 3 / | branch 2 / | 1 0 <-- first swap branch / | branch 3 / | branch 1 <-- second swap / | 2 0 branch / | branch 3 / | branch 1 / | 0 2 <-- third swap branch / | branch 3 / | branch 0 <-- fourth swap / | 1 2 and so on... Sorry for the ridiculisly long and waddly explanation, would really, really apreciate any sort of help you guys could offer me. Thanks a bunch!

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• How to get the related_name of a many-to-many-field?

  - by amann

  I am trying to get the related_name of a many-to-many-field. The m2m-field is located betweeen the models "Group" and "Lection" and is declared in the group-model as following: lections = models.ManyToManyField(Lection, blank=True) The field looks like this: <django.db.models.fields.related.ManyToManyField object at 0x012AD690> The print of field.__dict__ is: {'_choices': [], '_m2m_column_cache': 'group_id', '_m2m_name_cache': 'group', '_m2m_reverse_column_cache': 'lection_id', '_m2m_reverse_name_cache': 'lection', '_unique': False, 'attname': 'lections', 'auto_created': False, 'blank': True, 'column': 'lections', 'creation_counter': 71, 'db_column': None, 'db_index': False, 'db_table': None, 'db_tablespace': '', 'default': <class django.db.models.fields.NOT_PROVIDED at 0x00FC8780>, 'editable': True, 'error_messages': {'blank': <django.utils.functional.__proxy__ object at 0x00FC 7B50>, 'invalid_choice': <django.utils.functional.__proxy__ object at 0x00FC7A50>, 'null': <django.utils.functional.__proxy__ object at 0x00FC7 A70>}, 'help_text': <django.utils.functional.__proxy__ object at 0x012AD6F0>, 'm2m_column_name': <function _curried at 0x012A88F0>, 'm2m_db_table': <function _curried at 0x012A8AF0>, 'm2m_field_name': <function _curried at 0x012A8970>, 'm2m_reverse_field_name': <function _curried at 0x012A89B0>, 'm2m_reverse_name': <function _curried at 0x012A8930>, 'max_length': None, 'name': 'lections', 'null': False, 'primary_key': False, 'rel': <django.db.models.fields.related.ManyToManyRel object at 0x012AD6B0>, 'related': <RelatedObject: mymodel:group related to lections>, 'related_query_name': <function _curried at 0x012A8670>, 'serialize': True, 'unique_for_date': None, 'unique_for_month': None, 'unique_for_year': None, 'validators': [], 'verbose_name': 'lections'} Now the field should be accessed via a lection-instance. So this is done by lection.group_set But i need to access it dynamically, so there is the need to get the related_name attribute from somewhere. Here in the documentation, there is a note that it is possible to access ManyToManyField.related_name, but this doesn't work for my somehow.. Help would be a lot appreciated. Thanks in advance.

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• Search a string in a file and write the matched lines to another file in Java

  - by Geeta

  For searching a string in a file and writing the lines with matched string to another file it takes 15 - 20 mins for a single zip file of 70MB(compressed state). Is there any ways to minimise it. my source code: getting Zip file entries zipFile = new ZipFile(source_file_name); entries = zipFile.entries(); while (entries.hasMoreElements()) { ZipEntry entry = (ZipEntry)entries.nextElement(); if (entry.isDirectory()) { continue; } searchString(Thread.currentThread(),entry.getName(), new BufferedInputStream (zipFile.getInputStream(entry)), Out_File, search_string, stats); } zipFile.close(); Searching String public void searchString(Thread CThread, String Source_File, BufferedInputStream in, File outfile, String search, String stats) throws IOException { int count = 0; int countw = 0; int countl = 0; String s; String[] str; BufferedReader br2 = new BufferedReader(new InputStreamReader(in)); System.out.println(CThread.currentThread()); while ((s = br2.readLine()) != null) { str = s.split(search); count = str.length - 1; countw += count; //word count if (s.contains(search)) { countl++; //line count WriteFile(CThread,s, outfile.toString(), search); } } br2.close(); in.close(); } -------------------------------------------------------------------------------- public void WriteFile(Thread CThread,String line, String out, String search) throws IOException { BufferedWriter bufferedWriter = null; System.out.println("writre thread"+CThread.currentThread()); bufferedWriter = new BufferedWriter(new FileWriter(out, true)); bufferedWriter.write(line); bufferedWriter.newLine(); bufferedWriter.flush(); } Please help me. Its really taking 40 mins for 10 files using threads and 15 - 20 mins for a single file of 70MB after being compressed. Any ways to minimise the time.

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• how to retreive the row value on click

  - by kumar

  var RowClick = function() { ("#Grid").click( var s = $("#Grid").jqGrid('getGridParam', 'selarrrow').toString(); alert(s); $("#showgrid").load('/Inventory/Products/List/' + s)); }; on RowClick i am trying to get the value of that row to send throw URL.. to access this Row value in my Actionresult method. but I am getting null value for the row? is this right what I am doing here? Thanks When I am doing somethign like this.. var value; $("#Grid").click(function(e) { var row = jQuery(e.target).parent(); value= row.attr("id"); }); var RowClick = function() { ("#Grid").click( $("#showgrid").load('/Inventory/Products/List/' + value)); }; on alert I am getting the row value perfectly but in my action result method Its showing me null value? Public Actionresult List(string value) { return View(); } can anybody help me out.. thanks

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• Need a regular expression for an Irish phone number

  - by Eoghan O'Brien

  I need to validate an Irish phone number but I don't want to make it too user unfriendly, many people are used to writing there phone number with brackets wrapping their area code followed by 5 to 7 digits for their number, some add spaces between the area code or mobile operator. The format of Irish landline numbers is an area code of between 1 and 4 digits and a number of between 5 to 8 digits. e.g. (021) 9876543 (01)9876543 01 9876543 (0402)39385 I'm looking for a regular expression for Javascript/PHP. Thanks.

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• Improving File Read Performance (single file, C++, Windows)

  - by david

  I have large (hundreds of MB or more) files that I need to read blocks from using C++ on Windows. Currently the relevant functions are: errorType LargeFile::read( void* data_out, __int64 start_position, __int64 size_bytes ) const { if( !m_open ) { // return error } else { seekPosition( start_position ); DWORD bytes_read; BOOL result = ReadFile( m_file, data_out, DWORD( size_bytes ), &bytes_read, NULL ); if( size_bytes != bytes_read || result != TRUE ) { // return error } } // return no error } void LargeFile::seekPosition( __int64 position ) const { LARGE_INTEGER target; target.QuadPart = LONGLONG( position ); SetFilePointerEx( m_file, target, NULL, FILE_BEGIN ); } The performance of the above does not seem to be very good. Reads are on 4K blocks of the file. Some reads are coherent, most are not. A couple questions: Is there a good way to profile the reads? What things might improve the performance? For example, would sector-aligning the data be useful? I'm relatively new to file i/o optimization, so suggestions or pointers to articles/tutorials would be helpful.

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• MySQL get point in time totals from related tables

  - by batfastad

  Hi everyone We have an order book and invoicing system and I've been tasked with trying to output monthly rolling totals from these tables. But I don't know really where to start with this. I think there's some SQL syntax that I don't even know about yet. I'm familiar with INNER/LEFT/JOINS and GROUP BY etc but grouping by date is confusing since I don't know how to limit the data to only the current date that's being grouped by at that point. I think this will involve joining the tables to themselves or possibly a sub-select. I always thought it best to avoid sub-selects apart from when absolutely necessary. Basically the system has 3 tables orders: order_id, currency, order_stamp orders_lines: order_line_id, invoice_id, order_id, price invoices: invoice_id, invoice_stamp order_stamp and invoice_stamp are UTC unix timestamps stored as integers, not MySQL timestamps. I'm trying to get a listing by year/month showing the total of current unbilled orders (sum of price), at that point in time. Current orders are ones where order_stamp is less than or equal to 00:00 on the 1st of the month. Unbilled orders are ones where invoice_stamp is null or invoice_stamp is greater than 00:00 on the 1st of the month. At that point in time there may not be a related invoice yet and invoice_id might be null. Anyone got any suggestions on what I should join to what and what I need to group by? Cheers, B

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• How to use dirent.h correctly.

  - by Nick

  Hello, I am new to C++ and I am experimenting with the dirent.h header to manipulate directory entries. The following little app compiles but pukes after you supple a directory name. Can someone give me a hint? The int quit is there to provide a while loop. I removed the loop in an attempt to isolate my problem. thanks! #include <iostream> #include <dirent.h> using namespace std; int main() { char *dirname = 0; DIR *pd = 0; struct dirent *pdirent = 0; int quit = 1; cout<< "Enter a directory path to open (leave blank to quit):\n"; cin >> dirname; if(dirname == NULL) { quit = 0; } pd = opendir(dirname); if(pd == NULL) { cout << "ERROR: Please provide a valid directory path.\n"; } return 0; }

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• Exception in DatePickerDialog

  - by Miya

  Hi, i am trying to create a DatePickerDialog in the class 'dateDisplay.class'. I am calling this activity from 'main.class'. If I call the 'dateDisplay.class' using startActivity(), then the DatePickerDialog works fine. But actually I am using an ActivityGroup (for using tab in my application) and I am starting the 'dateDisplay.class' using the following code : Intent dateIntent=new Intent(context,dateDisplay.class); View v=getLocalActivityManager().startActivity("2",dateIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)).getDecorView(); setContentView(v); But an exception is caught, on calling the onCreateDialog() function. And the process is suddently stopped. It shows TargetInvocationException is occured. How can I correct the code? Following is my code: public Dialog onCreateDialog(int id,Bundle b) { Calendar c=Calendar.getInstance(); int day=c.get(Calendar.DAY_OF_MONTH); int month=c.get(Calendar.MONTH); int year=c.get(Calendar.YEAR); Dialog d = null; if(id==DATE_DIALOG_ID) { return new DatePickerDialog(this,dateChangeListener,year,month,day); } else { return null; } } Please help me.. Thank you..

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• How can I get type information at runtime from a DMP file in a Windbg extension?

  - by pj4533

  This is related to my previous question, regarding pulling objects from a dmp file. As I mentioned in the previous question, I can successfully pull object out of the dmp file by creating wrapper 'remote' objects. I have implemented several of these so far, and it seems to be working well. However I have run into a snag. In one case, a pointer is stored in a class, say of type 'SomeBaseClass', but that object is actually of the type 'SomeDerivedClass' which derives from 'SomeBaseClass'. For example it would be something like this: MyApplication!SomeObject +0x000 field1 : Ptr32 SomeBaseClass +0x004 field2 : Ptr32 SomeOtherClass +0x008 field3 : Ptr32 SomeOtherClass I need someway to find out what the ACTUAL type of 'field1' is. To be more specific, using example addresses: MyApplication!SomeObject +0x000 field1 : 0cae2e24 SomeBaseClass +0x004 field2 : 0x262c8d3c SomeOtherClass +0x008 field3 : 0x262c8d3c SomeOtherClass 0:000> dt SomeBaseClass 0cae2e24 MyApplication!SomeBaseClass +0x000 __VFN_table : 0x02de89e4 +0x038 basefield1 : (null) +0x03c basefield2 : 3 0:000> dt SomeDerivedClass 0cae2e24 MyApplication!SomeDerivedClass +0x000 __VFN_table : 0x02de89e4 +0x038 basefield1 : (null) +0x03c basefield2 : 3 +0x040 derivedfield1 : 357 +0x044 derivedfield2 : timecode_t When I am in WinDbg, I can do this: dt 0x02de89e4 And it will show the type: 0:000> dt 0x02de89e4 SomeDerivedClass::`vftable' Symbol not found. But how do get that inside an extension? Can I use SearchMemory() to look for 'SomeDerivedClass::`vftable'? If you follow my other question, I need this type information so I know what type of wrapper remote classes to create. I figure it might end up being some sort of case-statement, where I have to match a string to a type? I am ok with that, but I still don't know where I can get that string that represents the type of the object in question (ie SomeObject-field1 in the above example).

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• Subset and lagging list data structure R

  - by user1234440

  I have a list that is indexed like the following: >list.stuff [[1]] [[1]]$vector ... [[1]]$matrix .... [[1]]$vector [[2]] null [[3]] [[3]]$vector ... [[3]]$matrix .... [[3]]$vector . . . Each segment in the list is indexed according to another vector of indexes: >index.list 1, 3, 5, 10, 15 In list.stuff, only at each of the indexes 1,3,5,10,15 will there be 2 vectors and one matrix; everything else will be null like [[2]]. What I want to do is to lag like the lag.xts function so that whatever is stored in [[1]] will be pushed to [[3]] and the last one drops off. This also requires subsetting the list, if its possible. I was wondering if there exists some functions that handle list manipulation. My thinking is that for xts, a time series can be extracted based on an index you supply: xts.object[index,] #returns the rows 1,3,5,10,15 From here I can lag it with: lag.xts(xts.object[index,]) Any help would be appreciated thanks: EDIT: Here is a reproducible example: list.stuff<-list() vec<-c(1,2,3,4,5,6,7,8,9) vec2<-c(1,2,3,4,5,6,7,8,9) mat<-matrix(c(1,2,3,4,5,6,7,8),4,2) list.vec.mat<-list(vec=vec,mat=mat,vec2=vec2) ind<-c(2,4,6,8,10) for(i in ind){ list.stuff[[i]]<-list.vec.mat }

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• Non-normalized association with legacy tables in Rails and ActiveRecord

  - by Thomas Holmström

  I am building a Rails application accessing a legacy system. The data model contains Customers which can have one or more Subscriptions. A Subscription always belong to one and only one Customer. Though not needed, this association is represented through a join table "subscribes", which do not have an id column: Column | Type | Modifiers -----------------+---------+----------- customer_id | integer | not null subscription_id | integer | not null I have this coded as a has_and_belongs_to_many declarations in both Customer and Subscription class Customer < Activerecord::Base has_and_belongs_to_many :subscriptions, :join_table => "subscribes", :foreign_key => "customer_id", :association_foreign_key => "subscription_id" end class Subscription < Activerecord::Base has_and_belongs_to_many :customers, :join_table => "subscribes", :foreign_key => "subscription_id", :association_foreign_key => "customer_id" end The problem I have is that there can only ever be one customer for each subscription, not many, and the join table will always contain at most one row with a certain customer_id. And thus, I don't want the association "customers" on a Subscription which returns an array of (at most one) Customer, I really do want the relation "customer" which returns the Customer associated. Is there any way to force ActiveRecord to make this a 1-to-N relation even though the join table itself seems to make it an N-to-M relation? --Thomas

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• How to implement conditional render in JS?

  - by mare

  Below is the JS (jQuery) code of autocomplete's result function. You can see there's some lines where I print out <li>s containing some data properties (that come in as a result of automcomplete's AJAX call). How could I rewrite this so that <li> would be conditionally rendered based on whether the property contains any value being either int or string (not empty string or whitespace) or something else that can be represented as string? $(".clients-dropdown").result(function (event, data, formatted) { if (data) { // set the hidden input that we need for Client entity rematerialize $(".client-id").val(data.client_id); if (data.ClientName && data.Address1 && data.postalcode && data.postname) { $(".client-address").html( "<li>" + data.ClientName + "</li>" + "<li>" + data.Address1 + "</li>" + "<li>" + data.postalcode + " " + data.postname + "</li>" ); $(".client-details").html( "<li>" + data.PrettyId + "</li>" + "<li>" + data.VatNo + "</li>" + "<li>" + data.Phone + "</li>" + "<li>" + data.Mobile + "</li>" + "<li>" + data.Email1 + "</li>" + "<li>" + data.Contact + "</li>" ); } } Also, for the AJAX call, should my server side action return null when there's a null for a property in the database or empty string?

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• different explanation

  - by Delirium tremens

  The following code echoes 5, not 10: $global_obj = null; class my_class { var $value; function my_class() { global $global_obj; $global_obj = &$this; } } $a = new my_class; $a->my_value = 5; $global_obj->my_value = 10; echo $a->my_value; "Upon first examination, it would seem that the constructor of my_class stores a reference to itself inside the $global_obj variable. Therefore, one would expect that, when we later change the value of $global_obj-my_value to 10, the corresponding value in $a would change as well. Unfortunately, the new operator does not return a reference, but a copy of the newly created object." Please, give me a different explanation.

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• Problem convert column values from VARCHAR(n) to DECIMAL

  - by Kevin Babcock

  I have a SQL Server 2000 database with a column of type VARCHAR(255). All the data is either NULL, or numeric data with up to two points of precision (e.g. '11.85'). I tried to run the following T-SQL query but received the error 'Error converting data type varchar to numeric' SELECT CAST([MyColumn] AS DECIMAL) FROM [MyTable]; I tried a more specific cast, which also failed. SELECT CAST([MyColumn] AS DECIMAL(6,2)) FROM [MyTable]; I also tried the following to see if any data is non-numeric, and the only values returned were NULL. SELECT ISNUMERIC([MyColumn]), [MyColumn] FROM [MyTable] WHERE ISNUMERIC([MyColumn]) = 0; I tried to convert to other data types, such as FLOAT and MONEY, but only MONEY was successful. So I tried the following: SELECT CAST(CAST([MyColumn] AS MONEY) AS DECIMAL) FROM [MyTable]; ...which worked just fine. Any ideas why the original query failed? Will there be a problem if I first convert to MONEY and then to DECIMAL? Thanks!

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• socket timeout and remove O_NONBLOCK option

  - by juxstapose

  Hello, I implemented a socket timeout and retry but in order to do it I had to set the socket as a non-blocking socket. However, I need the socket to block. This was my attempt at a solution to these two problems. This is not working. Subsequent send calls block but never send any data. When I connect without the select and the timeout, subsequent send calls work normally. References: C: socket connection timeout How to reset a socket back to blocking mode (after I set it to nonblocking mode)? Code: fd_set fdset; struct timeval tv; fcntl(dsock, F_SETFL, O_NONBLOCK); tv.tv_sec = theDeviceTimeout; tv.tv_usec = 0; int retries=0; logi(theLogOutput, LOG_INFO, "connecting to device socket num retrys: %i", theDeviceRetry); for(retries=0;retries<theDeviceRetry;retries++) { connect(dsock, (struct sockaddr *)&daddr, sizeof daddr); FD_ZERO(&fdset); FD_SET(dsock, &fdset); if (select(dsock + 1, NULL, &fdset, NULL, &tv) == 1) { int so_error; socklen_t slen = sizeof so_error; getsockopt(dsock, SOL_SOCKET, SO_ERROR, &so_error, &slen); if (so_error == 0) { logi(theLogOutput, LOG_INFO, "connected to socket on port %i on %s", theDevicePort, theDeviceIP); break; } else { logi(theLogOutput, LOG_WARN, "connect to %i failed on ip %s because %s retries %i", theDevicePort, theDeviceIP, strerror(errno), retries); logi(theLogOutput, LOG_WARN, "failed to connect to device %s", strerror(errno)); logi(theLogOutput, LOG_WARN, "error: %i %s", so_error, strerror(so_error)); continue; } } } int opts; opts = fcntl(dsock,F_GETFL); logi(theLogOutput, LOG_DEBUG, "clearing nonblock option %i retries %i", opts, retries); opts ^= O_NONBLOCK; fcntl(dsock, F_SETFL, opts);

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• Is there an existing algorithm for this notation translation/conversion?

  - by John

  A system has a notation that would require writing an expression like (A+B)*C as #MUL(#ADD(A,B),C). Is there already an algorithm to do this kind of notation conversion so users can enter in a more conventional way? In other words an algorithm to convert from infix - my notation. First issue is I don't know an exact name for my notation... it's similar to reverse-polish but not quite. Every operator is encoded as a function taking arguments.

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• Passing javascript object to webservice via Jquery ajax

  - by kralco626

  I have a webservice that returns an object [WebMethod] public List<User> ContractorApprovals() I also have a webservice that accepcts an object [WebMethod] public bool SaveContractor(Object u) When I make my webservice calls via Jquery: function ServiceCall(method, parameters, onSucess, onFailure) { var parms = "{" + (($.isArray(parameters)) ? parameters.join(',') : parameters) + "}"; // to json $.ajax({ type: "POST", url: "services/"+method, data: parms, contentType: "application/json; charset=utf-8", dataType: "json", success: function(msg) { if (typeof onSucess == 'function' || typeof onSucess == 'object') onSucess(msg.d); }, error: function(msg, err) { $("#dialog-error").dialog('open');} }); I can call the first one just fine. My onSucess function gets passed a javascript object exactly structured like my User object on the service. However, I am now having trouble getting the object back to the server. I'm accepting Object as a parameter on the server side so I can't inagine there is an issue there. So I'm thinking something is wrong with the parms on the client side but i'm not sure what... I am doing something to the effect ServiceCall("AuthorizationManagerWorkManagement.asmx/ContractorApprovals", "", function(data,args){$("#div").data('user',data[0])}, null) then ServiceCall("AuthorizationManagerWorkManagement.asmx/SaveContractor", $("#div").data('user'), //These also do not work: "{'u': ' + $("#div").data("user") + '}", NOR JSON.stringify({u: userObject}) function(data,args){(alert(data)}, null) I know the first service call works, I can get the data. The second one is causing the "onFailure" method to execute rather then "OnSuccess". Any ideas?

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• is this a simple monad example?

  - by zcaudate

  This is my attempt to grok monadic functions after watching http://channel9.msdn.com/Shows/Going+Deep/Brian-Beckman-Dont-fear-the-Monads. h uses bind to compose together two arbitrary functions f and g. What is the unit operator in this case? ;; f :: int - [str] ;; g :: str = [keyword] ;; bind :: [str] - (str - [keyword]) - [keyword] ;; h :: int - [keyword] (defn f [v] (map str (range v))) (defn g [s] (map keyword (repeat 4 s))) (defn bind [l f] (flatten (map f l))) (f 8) ;; = (0 1 2 3 4 5 6 7) (g "s") ;; = (:s :s :s :s) (defn h [v] (bind (f v) g)) (h 9) ;; = (:0 :0 :0 :0 :1 :1 :1 :1 :2 :2 :2 :2 :3 :3 :3 :3 :4 :4 :4 :4 :5 :5 :5 :5)

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• caching previous return values of procedures in scheme

  - by Brock

  In Chapter 16 of "The Seasoned Schemer", the authors define a recursive procedure "depth", which returns 'pizza nested in n lists, e.g (depth 3) is (((pizza))). They then improve it as "depthM", which caches its return values using set! in the lists Ns and Rs, which together form a lookup-table, so you don't have to recurse all the way down if you reach a return value you've seen before. E.g. If I've already computed (depthM 8), when I later compute (depthM 9), I just lookup the return value of (depthM 8) and cons it onto null, instead of recursing all the way down to (depthM 0). But then they move the Ns and Rs inside the procedure, and initialize them to null with "let". Why doesn't this completely defeat the point of caching the return values? From a bit of experimentation, it appears that the Ns and Rs are being reinitialized on every call to "depthM". Am I misunderstanding their point? I guess my question is really this: Is there a way in Scheme to have lexically-scoped variables preserve their values in between calls to a procedure, like you can do in Perl 5.10 with "state" variables?

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• DataSet with many OR clauses

  - by Silvan

  Hello :) I've got a little problem with a query which I create in the Visual Studio Designer. I need a query with a lot of 'OR'-clauses for the same column. I found the operator 'IN', but I don't know how to use that in the Visual Studio Designer: Example IN: SELECT EmployeeID, FirstName, LastName, HireDate, City FROM Employees WHERE City IN ('Seattle', 'Tacoma', 'Redmond') I tried to do it in this way: SELECT [MachineryId], [ConstructionSiteId], [DateTime], [Latitude], [Longitude], [HoursCounter] FROM [PositionData] WHERE [MachineryID] IN @MachineryIDs But this doesn't work. Is there another way to handle a lot of OR clauses? Thank you very much for your help.

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• How do you get the logical xor of two variables in Python?

  - by Zach Hirsch

  How do you get the logical xor of two variables in Python? For example, I have two variables that I expect to be strings. I want to test that only one of them contains a True value (is not None or the empty string): str1 = raw_input("Enter string one:") str2 = raw_input("Enter string two:") if logical_xor(str1, str2): print "ok" else: print "bad" The ^ operator seems to be bitwise, and not defined on all objects: >>> 1 ^ 1 0 >>> 2 ^ 1 3 >>> "abc" ^ "" Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unsupported operand type(s) for ^: 'str' and 'str'

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• Problem in getting response from server in jquery

  - by Alvin

  Hello, I'm using $.ajax(options) method to pass the request to server based on username and password, but whenever I try to print the response by XMLHttpRequest object when response gets successful, I'm getting an empty value. $(document).ready(function(){ $("#form").submit(function(){ $.ajax({url:"Chat.jsp",type:"POST",data:$("#form").serialize(),success:function(request) { alert(request.responseText); //This is displaying nothing },error:function(){document.write("YOU can't");}}); }); }); This is what I'm doing in my servlets code after executing query: try { String user = request.getParameter("j_username"); String password = request.getParameter("j_password"); if(user != null && password != null) { String query = "Select * from users where user_name="+"\'"+user+"\'"+"&& user_pass="+"\""+password+"\""; DBCheck db= new DBCheck(); boolean b = db.doExecuteQuery(con.createStatement(),query); response.setHeader("Cache-Control", "no-cache"); if(b) { response.getWriter().println("Username already exits"); } else { response.getWriter().println("Username doesn't exit"); } } } catch(SQLException ex) { ex.printStackTrace(); } } May I know the problem, and how can I fix it?

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• Can't seem to get .Union to work (merging 2 array's together, exclude duplicates)

  - by D. Veloper

  I want to combine two array's, excluding duplicates. I am using a custom class: public class ArcContact : IEquatable<ArcContact> { public String Text; public Boolean Equals(ArcContact other) { if (Object.ReferenceEquals(other, null)) return false; if (Object.ReferenceEquals(this, other)) return true; return Text.Equals(other.Text); } public override Int32 GetHashCode() { return Text == null ? 0 : Text.GetHashCode(); } } I implemented and the needed IEquatable interface as mentioned in this msdn section. I only want to check the Text property of the ArcContact class and make sure an Array of ArcContact have an unique Text. Here I pasted the code that I use, as you can see I have method with two parameters, array's to combine and below that the code I got from the previous mentioned msdn section. internal static class ArcBizz { internal static ArcContact[] MergeDuplicateContacts(ArcContact[] contacts1, ArcContact[] contacts2) { return (ArcContact[])contacts1.Union(contacts2); } internal static IEnumerable<T> Union<T>(this IEnumerable<T> a, IEnumerable<T> b); } What am I doing wrong?

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• What is the easiest way to get the property value from a passed lambda expression in an extension me

  - by Andrew Siemer

  I am writing a dirty little extension method for HtmlHelper so that I can say something like HtmlHelper.WysiwygFor(lambda) and display the CKEditor. I have this working currently but it seems a bit more cumbersome than I would prefer. I am hoping that there is a more straight forward way of doing this. Here is what I have so far. public static MvcHtmlString WysiwygFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression) { return MvcHtmlString.Create(string.Concat("<textarea class=\"ckeditor\" cols=\"80\" id=\"", expression.MemberName(), "\" name=\"editor1\" rows=\"10\">", GetValue(helper, expression), "</textarea>")); } private static string GetValue<TModel, TProperty>(HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression) { MemberExpression body = (MemberExpression)expression.Body; string propertyName = body.Member.Name; TModel model = helper.ViewData.Model; string value = typeof(TModel).GetProperty(propertyName).GetValue(model, null).ToString(); return value; } private static string MemberName<T, V>(this Expression<Func<T, V>> expression) { var memberExpression = expression.Body as MemberExpression; if (memberExpression == null) throw new InvalidOperationException("Expression must be a member expression"); return memberExpression.Member.Name; } Thanks!

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