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• How to select rows from data.frame with 2 conditions

  - by Peter Smit

  I have an aggregated table: > aggdata[1:4,] Group.1 Group.2 x 1 4 0.05 0.9214660 2 6 0.05 0.9315789 3 8 0.05 0.9526316 4 10 0.05 0.9684211 How can I select the x value when I have values for Group.1 and Group.2? I tried: aggdata[aggdata[,"Group.1"]==l && aggdata[,"Group.2"]==lamda,"x"] but that replies all x's. More info: I want to use this like this: table = data.frame(); for(l in unique(aggdata[,"Group.1"])) { for(lambda in unique(aggdata[,"Group.2"])) { table[l,lambda] = aggdata[aggdata[,"Group.1"]==l & aggdata[,"Group.2"]==lambda,"x"] } } Any suggestions that are even easier and giving this result I appreciate!

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• How to do this query?

  - by Damiano

  Hello everybody! I have a mysql table with these columns: ID (auto-increment) ID_BOOK (int) PRICE (double) DATA (date) I know two ID_BOOK values, example, 1 and 2. QUERY: I have to extract all the PRICE (of the ID_BOOK=1 and ID_BOOK=2) where DATA is the same! Table example: 1 1 10.00 2010-05-16 2 1 11.00 2010-05-15 3 1 12.00 2010-05-14 4 2 18.00 2010-05-16 5 2 11.50 2010-05-15 Result example: 1 1 10.00 2010-05-16 4 2 18.00 2010-05-16 2 1 11.00 2010-05-15 5 2 11.50 2010-05-15 ID_BOOK=2 hasn't 2010-05-14 so i jump it. Thank you so much!

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• Can I use a single MySQL query to select distinct rows and then non-distinct rows if a limit hasn't

  - by Matt Rix

  I hope I'm explaining this properly, my knowledge of MySQL is quite limited. Let's say I have a table with rows that have name and shape fields. I'd like to select a bunch of rows from a table, but return all of the rows with unique shape field values first. If I have less than a certain number of rows, let's say 7, then I'd like to fill the remaining result rows with non-unique shape rows. The best way I can word it is that they're "ordered by uniqueness, and then by some other value". So, I don't want: square, square, circle, circle, rectangle, square, triangle I'd like to have: square, circle, rectangle, triangle, square, square, circle Is this possible to do using a single SQL query? I'm using MySQL with PHP, if that makes any difference. Thanks!

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• Oracle PL/SQL: Dump query result into file

  - by CC

  Hi. I'm working on a pl sql stored procedure. What I need is to do a select, use a cursor and for every record build a string using values. At the end I need to write this into a file. I try to use dbms_output.put_line("toto") but the buffer size is to small because I have about 14 millions lines. I call my procedure from a unix ksh. I'm thinking at something like using "spool on" (on the ksh side) to dump the result of my procedure, but I don' know how to do it (if this is possible) Anyone has any idea? Thank alot. C.C.

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• Ternary operators and variable reassignment in PHP

  - by TomcatExodus

  I've perused the questions on ternary operators vs. if/else structures, and while I understand that under normal circumstances there is no performance loss/gain in using ternary operators over if/else structures, I've not seen any mention of this situation. Language specific to PHP (but any language agnostic details are welcome) does the interpreter reassign values in situations like this: $foo = 'bar' $foo = strlen($foo) > 3 ? substr($foo, 0, 3) : $foo; Since this would evaluate to $foo = $foo; is this inefficient, or does the interpreter simply overlook/discard this evaluation? On a side note, what about: !defined('SECURE') ? exit : null;

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• Lexical Analyzer(Scanner) for Language G by using C/C++

  - by udsha

  int a = 20; int b =30; float c; c = 20 + a; if(c) { a = c*b + a; } else { c = a - b + c; } use C++ / C to Implement a Lexer. 1. Create Unambiguous grammer for language G. 2. Create Lexical Analyzer for Language G. 3. It should identified tokens and lexemes for that language. 4. create a parse tree. 5. to use attribute grammer on a parse tree the values of the intrinsic attributes should be available on the symbol table.

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• how to get the value entered in combobox that is binded to datagridview

  - by Ranjana

  i have dynamically added combobox to datagridview. in this gridview i need to enter the values to combobox. but it is not allowing me to enter the value. code: if (strtype.Contains("ComboBox")) { checkcmbColumn.Name = strControlName; checkcmbColumn.HeaderText = strColumnName; checkcmbColumn.HeaderCell.Style.Alignment = DataGridViewContentAlignment.MiddleCenter; checkcmbColumn.Width = 100; checkcmbColumn.ReadOnly = false; checkcmbColumn.Items.Add("1"); checkcmbColumn.Items.Add("2"); GrdViewDetails.Columns.Add(checkcmbColumn); }

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• Exponential volume control with a specified midpoint

  - by Lars

  I have a slider that returns values from 0 to 100. I am using this to control the gain of an oscillator. When the slider is at 0, I would like the gain to be 0.0 When the slider is at 50, I would like the gain to be 0.1 When the slider is at 100, I would like the gain to be 0.5 So I need to find an equation to get a smooth curve which passes through all of these points. I've got the following equation which gives an exponential curve and gets the start and end points correct, but I don't know how to force the curve through the middle point. Can anyone help? function logSlider(position){ var minP = 0; var maxP = 100; var minV = Math.log(0.0001); var maxV = Math.log(0.5); var scale = (maxV - minV) / (maxP - minP); return Math.exp(minV + scale*(position-minP)); }

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• Store the day of the week and time

  - by bsiddiqui

  I have a two part question about storing day(s) of the week and time in a database. I'm using Rails 4.0, ruby 2.0.0, and postgres. I have certain events and those events have a schedule. For the event Skydiving for example, for example, I might have Tuesday and Wednesday and 3 pm. 1) Is there a way for me to store the the record for Tuesday and Wednesday in one row or do should I have two records? 2) What is the best way to store the day and time? Is there a way to store day of week and time (not datetime) or should these be separate columns? If they should be separate, how would you store day of week? I was thinking of storing them as integer values (0 for Sunday, 1 for Monday, etc) since that's how wday method for the Time class does it. Any suggestions would be super helpful. Thanks!

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• Statistics Question: Kernel Smoothing in R

  - by James Thompson

  I have data of this form: x y 1 0.19 2 0.26 3 0.40 4 0.58 5 0.59 6 1.24 7 0.68 8 0.60 9 1.12 10 0.80 11 1.20 12 1.17 13 0.39 I'm currently plotting a kernel-smoothed density estimate of the x versus y using this code: smoothed = ksmooth( d$resi, d$score, bandwidth = 6 ) plot( smoothed ) I simply want a plot of the x versus smoothed(y) values, which is ## Heading ## However, the documentation for ksmooth suggests that this isn't the best kernel-smoothing package available: This function is implemented purely for compatibility with S, although it is nowhere near as slow as the S function. Better kernel smoothers are available in other packages. What other kernel smoothers are better can these smoothers be found?

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• Using new to allocate an array of class elements with an overloaded constructor in C++.

  - by GordoN

  As an example say I have a class foo that does not have a default constructor but one that looks like this foo:foo(int _varA,int _varB) { m_VarA = _varA; m_VarB = _varB; } How would I allocate an array of these. I seem to remember trying somthing like this unsuccessfully. foo* MyArray = new foo[100](25,14). I don't think this will work either. foo* MyArray = new foo[100](25,14) Can this be done? I typically do this by writing the default constructor using some preset values for _varA and _varB. Then adding a function to reset _varA and _varB for each element but that will not work for this case. Thanks for the help.

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• getting the value of a filter at an arbitrary time

  - by Andiih

  Context: I'm trying to improve the values returned by the iPhone CLLocationManager, although this is a more generally applicable problem. The key is that CLLocationManger returns data on current velocity as and when it feels like it, rather than at a fixed sample rate. I'd like to use a feedback equation to improve accuracy v=(k*v)+(1-k)*currentVelocity where currentVelocity is the speed returned by didUpdateToLocation:fromLocation: and v is the output velocity (and also used for the feedback element). Because of the "as and when" nature of didUpdateToLocation:fromLocation: I could calculate the time interval since it was last called, and do something like for (i=0;i<timeintervalsincelastcalled;i++) v=(k*v)+(1-k)*currentVelocity which would work, but is wasteful of cycles. Especially as I probably want timeintervalsincelastcalled to be measured as 10ths of a second. Is there a way to solve this without the loop ? i.e. rework (integrate?) the formula so I put an interval into the equation and get the same answer as I would have by iteration ?

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• C# ToDictionary can valueSelector give null?

  - by Trimack

  Hi, I want to make a dictionary out of list in a way, that the list becomes keys and values would be empty. I have following code Dictionary<XmlTest, int?> testBattery = new XmlTests().GetRandomTestBattery(id). ToDictionary(k => k, v => null); But I am getting the error "Cannot convert lambda expression to type System.Collections.Generic.IEqualityComparer' because it is not a delegate type" Any ideas how could I fix it? (I know I could iterate through and fill the dict one element at a time, but I simply want to use something more elegant)

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• Searching within an array of strings...

  - by SoLoGHoST

  Ok, I'm feeling retarded here, I have a string like so: $string = 'function module_testing{'; or it could be like this: $string = 'function module_testing'; And than I have an array of strings like so: $string_array = array('module_testing', 'another_function', 'and_another_function'); Now, is there some sort of preg_match that I can do to test if any of the $string_array values are found within the $string string at any given position? So in this situation, there would be a match. Or is there a better way to do this? I can't use in_array since it's not an exact match, and I'd rather not do a foreach loop on it if I can help it, since it's already in a while loop. Thanks :)

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• Returning a users lat lng as a string iPhone

  - by Joshmattvander

  Is there a way to return the users location as a string from a model? I have a model thats job is to download same JSON data from a web service. When sending in my request I need to add ?lat=LAT_HERE&lng=LNG_HERE to the end of the string. I have seen tons of examples using the map or constantly updating a label. But I cant find out how to explicitly return the lat and lng values. Im only 2 days into iPhone dev so go easy on me :)

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• convert std object class to comma seperated string

  - by Kwaasi Djin

  I have an std class object from twitter and i would like to take the ids array values and put them in a php variable $ids where $ids = (15761916,30144785,382747195,19399719). I imagine using a for loop and using phps implode but i'm not sure how to go about it. stdClass Object ( [ids] => Array ( [0] => 15761916 [1] => 30144785 [2] => 382747195 [3] => 19399719 ) [next_cursor] => 0 [next_cursor_str] => 0 [previous_cursor] => 0 [previous_cursor_str] => 0 )

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• How to fetch managed objects sorted by calculated value

  - by Marcin Zbijowski

  Hello, I'm working on the app that uses CoreData. There is location entity that holds latitude and longitude values. I'd like to fetch those entities sorted by distance to the user's location. I tried to set sort descriptor to distance formula sqrt ((x1 - x2)^2 + (y1 - y2)^2) but it fails with exception "... keypath ... not found in entity". NSString *distanceFormula = [NSString stringWithFormat:@"sqrt(((latitude - %f) * (latitude - %f)) + ((longitude - %f) * (longitude - %f)))", location.coordinate.latitude, location.coordinate.latitude, location.coordinate.longitude, location.coordinate.longitude]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:distanceFormula ascending:YES]; [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]]; NSError *error; NSArray *result = [[self managedObjectContext] executeFetchRequest:fetchRequest error:&error]; I'd like to fetch already sorted objects rather then fetch them all and then sort in the code. Any tips appreciated.

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• NSUserDefaults with in-app Settings bundle

  - by Hema Vasudevan

  I'm in the process of building an app and would prefer to have an in-app specific Settings bundle rather than make it available in the Settings application. I'm using NSUserDefaults class to save and retrieve them but would like to have the same Settings app look and feel. I wanted to use InAppSettingsKit or the llamasettings but don't know how to use the NSUserDefaults class. Those kits tell me how to create a .plist file and use their kits. All I need is use the Settings app look and feel while at the same time use NSUserDefaults class to save and retrieve values. Please help.

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• Iterate over a list and put data in hashmap

  - by sarah

  I am having a list where i need to loop over it and put its data in hashmap,i am using this approach for(int i=0;i<list.size();i++) { HashMap hMap=new HashMap(); hMap.put("Data", list); } But when i need to read the value from hMap i am doing in this way Collection c = hMap.values(); Iterator itr = c.iterator(); while(itr.hasNext()) { System.out.println("next val is--"+itr.next()); } next vali is--- is printed in com.bean.xyz@23032bc[id=1] format ,i need the exact data,how will i do this ?

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• How to raise CComponent event in Yii

  - by srigi

  Let's assume I have Component (say Graph like Yahoo Finance) rendered on the page. Component view template contains bunch of a_hrefs which I wanto to switch period in graph. I created Event and Event handler in Component. I have two questions: How to raise event on Graph Component via those a_hrefs (should they be part of Graph?)? How to redraw Graph without loosing curent page context (section, filter - specified as $_GET values)? My Graph Component look like this: Yii::import('zii.widgets.CPortlet'); class Graph extends CPortlet { private $_period; /* ********************** * * COMPONENT PROPERTIES * * ********************** */ public function getPeriod() { return $this-_period; } public function setPeriod($period) { $this-_period = $period; } /* ********************** * * GENERIC * * ********************** */ public function init() { parent::init(); // assign event handlers $this-onPeriodChange = array($this, 'handlePeriodChange'); } protected function renderContent() { $this-render('graph'); } /* ********************** * * EVENTS * * ********************** */ public function onPeriodChange($event) { $this-raiseEvent('onPeriodChange', $event); } /* ********************** * * EVENT HANDLERS * * ********************** */ public function handlePeriodChange($event) { // CODE } }

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• Using ggplot in R

  - by g256

  I have a time series cvs file like this (in var there are the values): Hour,Date,Type,val1,val2,val3,val4,val5,val6..... 0100,0153,aaa, 0100,0153,bbb, 0100,0153,ccc, 0100,0153,ddd, 0200,0153,aaa, 0200,0153,bbb, 0200,0153,ccc, 0200,0153,ddd, . . 0100,0154,aaa, 0100,0154,bbb, 0100,0154,ccc, 0100,0154,ddd, . . I would like to use ggplot to plot the barplot mean of the time series of val1,val2,... for each type. One plot for each type except for ccc and ddd that should be considered as one type, so for this I should first sum up the value, then take the mean, then plot). So three plot at the end. Thanks for advice.

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• why single SQL delete statement will cause deadlock?

  - by George2

  Hello everyone, I am using SQL Server 2008 Enterprise. I am wondering why even a single delete statement of this store procedure will cause deadlock if executed by multiple threads at the same time? For the delete statement, Param1 is a column of table FooTable, Param1 is a foreign key of another table (refers to another primary key clustered index column of the other table). There is no index on Param1 itself for table FooTable. FooTable has another column which is used as clustered primary key, but not Param1 column. create PROCEDURE [dbo].[FooProc] ( @Param1 int ,@Param2 int ,@Param3 int ) AS DELETE FooTable WHERE Param1 = @Param1 INSERT INTO FooTable ( Param1 ,Param2 ,Param3 ) VALUES ( @Param1 ,@Param2 ,@Param3 ) DECLARE @ID bigint SET @ID = ISNULL(@@Identity,-1) IF @ID > 0 BEGIN SELECT IdentityStr FROM FooTable WHERE ID = @ID END thanks in advance, George

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• Asp.net Page and control Events

  - by andrewWinn

  I have looked all over the web and I can not find the information I am looking for and I was hoping that someone could give me a hand. Specifically, I am looking for a comprehensive list of what events occur in the page and control life cycles and what is "available" in each event. Like when can I get a dropdownlists selected value, when can i databind, when can I get at values in view state and what not. Can anyone point me to a comprehensive list for both page and control life cycles? Or even provide that information for me? Thanks in advance.

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• Writing to pointer out of bounds after malloc() not causing error

  - by marr

  Hi, when I try the code below it works fine. Am I missing something? main() { int *p; p=malloc(sizeof(int)); printf("size of p=%d\n",sizeof(p)); p[500]=999999; printf("p[0]=%d",p[500]); return 0; } I tried it with malloc(0*sizeof(int)) or anything but it works just fine. The program only crashes when I don't use malloc at all. So even if I allocate 0 memory for the array p, it still stores values properly. So why am I even bothering with malloc then?

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• dropdown list selected index changed

  - by KareemSaad

  I did my drop down list that get it,s values from database and when run the application it didnot work and compiler didnot see the code onselectedindexchanged="DDlProductFamily_SelectedIndexChanged" protected void DDlProductFamily_SelectedIndexChanged(object sender, EventArgs e) { using (SqlConnection Con = Connection.GetConnection()) { SqlCommand Com = new SqlCommand("SelectThumbByProductFamily", Con); Com.CommandType = CommandType.StoredProcedure; Com.Parameters.Add(Parameter.NewInt("@ProductCategory_Id", DDlProductFamily.SelectedValue.ToString())); SqlDataAdapter DA = new SqlDataAdapter(Com); DA.Fill(dt); DataList1.DataSource = dt; DataList1.DataBind(); } }

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