Search Results

Search found 35387 results on 1416 pages for 'string substitution'.

Page 218/1416 | < Previous Page | 214 215 216 217 218 219 220 221 222 223 224 225  | Next Page >

  • Are there any working implementations of the rolling hash function used in the Rabin-Karp string sea

    - by c14ppy
    I'm looking to use a rolling hash function so I can take hashes of n-grams of a very large string. For example: "stackoverflow", broken up into 5 grams would be: "stack", "tacko", "ackov", "ckove", "kover", "overf", "verfl", "erflo", "rflow" This is ideal for a rolling hash function because after I calculate the first n-gram hash, the following ones are relatively cheap to calculate because I simply have to drop the first letter of the first hash and add the new last letter of the second hash. I know that in general this hash function is generated as: H = c1ak - 1 + c2ak - 2 + c3ak - 3 + ... + cka0 where a is a constant and c1,...,ck are the input characters. If you follow this link on the Rabin-Karp string search algorithm , it states that "a" is usually some large prime. I want my hashes to be stored in 32 bit integers, so how large of a prime should "a" be, such that I don't overflow my integer? Does there exist an existing implementation of this hash function somewhere that I could already use? Here is an implementation I created: public class hash2 { public int prime = 101; public int hash(String text) { int hash = 0; for(int i = 0; i < text.length(); i++) { char c = text.charAt(i); hash += c * (int) (Math.pow(prime, text.length() - 1 - i)); } return hash; } public int rollHash(int previousHash, String previousText, String currentText) { char firstChar = previousText.charAt(0); char lastChar = currentText.charAt(currentText.length() - 1); int firstCharHash = firstChar * (int) (Math.pow(prime, previousText.length() - 1)); int hash = (previousHash - firstCharHash) * prime + lastChar; return hash; } public static void main(String[] args) { hash2 hashify = new hash2(); int firstHash = hashify.hash("mydog"); System.out.println(firstHash); System.out.println(hashify.hash("ydogr")); System.out.println(hashify.rollHash(firstHash, "mydog", "ydogr")); } } I'm using 101 as my prime. Does it matter if my hashes will overflow? I think this is desirable but I'm not sure. Does this seem like the right way to go about this?

    Read the article

  • Why doesn't my implementation of El Gamal work for long text strings?

    - by angstrom91
    I'm playing with the El Gamal cryptosystem, and my goal is to be able to encipher and decipher long sequences of text. I have come up with a method that works for short sequences, but does not work for long sequences, and I cannot figure out why. El Gamal requires the plaintext to be an integer. I have turned my string into a byte[] using the .getBytes() method for Strings, and then created a BigInteger out of the byte[]. After encryption/decryption, I turn the BigInteger into a byte[] using the .toByteArray() method for BigIntegers, and then create a new String object from the byte[]. This works perfectly when i call ElGamalEncipher with strings up to 129 characters. With 130 or more characters, the output produced is garbled. Can someone suggest how to solve this issue? Is this an issue with my method of turning the string into a BigInteger? If so, is there a better way to turn my string of text into a BigInteger and back? Below is my encipher/decipher code with a program to demonstrate the problem. import java.math.BigInteger; public class Main { static BigInteger P = new BigInteger("15893293927989454301918026303382412" + "2586402937727056707057089173871237566896685250125642378268385842" + "6917261652781627945428519810052550093673226849059197769795219973" + "9423619267147615314847625134014485225178547696778149706043781174" + "2873134844164791938367765407368476144402513720666965545242487520" + "288928241768306844169"); static BigInteger G = new BigInteger("33234037774370419907086775226926852" + "1714093595439329931523707339920987838600777935381196897157489391" + "8360683761941170467795379762509619438720072694104701372808513985" + "2267495266642743136795903226571831274837537691982486936010899433" + "1742996138863988537349011363534657200181054004755211807985189183" + "22832092343085067869"); static BigInteger R = new BigInteger("72294619754760174015019300613282868" + "7219874058383991405961870844510501809885568825032608592198728334" + "7842806755320938980653857292210955880919036195738252708294945320" + "3969657021169134916999794791553544054426668823852291733234236693" + "4178738081619274342922698767296233937873073756955509269717272907" + "8566607940937442517"); static BigInteger A = new BigInteger("32189274574111378750865973746687106" + "3695160924347574569923113893643975328118502246784387874381928804" + "6865920942258286938666201264395694101012858796521485171319748255" + "4630425677084511454641229993833255506759834486100188932905136959" + "7287419551379203001848457730376230681693887924162381650252270090" + "28296990388507680954"); public static void main(String[] args) { FewChars(); System.out.println(); ManyChars(); } public static void FewChars() { //ElGamalEncipher(String plaintext, BigInteger p, BigInteger g, BigInteger r) BigInteger[] cipherText = ElGamal.ElGamalEncipher("This is a string " + "of 129 characters which works just fine . This is a string " + "of 129 characters which works just fine . This is a s", P, G, R); System.out.println("This is a string of 129 characters which works " + "just fine . This is a string of 129 characters which works " + "just fine . This is a s"); //ElGamalDecipher(BigInteger c, BigInteger d, BigInteger a, BigInteger p) String output = ElGamal.ElGamalDecipher(cipherText[0], cipherText[1], A, P); System.out.println("The decrypted text is: " + output); } public static void ManyChars() { //ElGamalEncipher(String plaintext, BigInteger p, BigInteger g, BigInteger r) BigInteger[] cipherText = ElGamal.ElGamalEncipher("This is a string " + "of 130 characters which doesn’t work! This is a string of " + "130 characters which doesn’t work! This is a string of ", P, G, R); System.out.println("This is a string of 130 characters which doesn’t " + "work! This is a string of 130 characters which doesn’t work!" + " This is a string of "); //ElGamalDecipher(BigInteger c, BigInteger d, BigInteger a, BigInteger p) String output = ElGamal.ElGamalDecipher(cipherText[0], cipherText[1], A, P); System.out.println("The decrypted text is: " + output); } } import java.math.BigInteger; import java.security.SecureRandom; public class ElGamal { public static BigInteger[] ElGamalEncipher(String plaintext, BigInteger p, BigInteger g, BigInteger r) { // returns a BigInteger[] cipherText // cipherText[0] is c // cipherText[1] is d SecureRandom sr = new SecureRandom(); BigInteger[] cipherText = new BigInteger[2]; BigInteger pText = new BigInteger(plaintext.getBytes()); // 1: select a random integer k such that 1 <= k <= p-2 BigInteger k = new BigInteger(p.bitLength() - 2, sr); // 2: Compute c = g^k(mod p) BigInteger c = g.modPow(k, p); // 3: Compute d= P*r^k = P(g^a)^k(mod p) BigInteger d = pText.multiply(r.modPow(k, p)).mod(p); // C =(c,d) is the ciphertext cipherText[0] = c; cipherText[1] = d; return cipherText; } public static String ElGamalDecipher(BigInteger c, BigInteger d, BigInteger a, BigInteger p) { //returns the plaintext enciphered as (c,d) // 1: use the private key a to compute the least non-negative residue // of an inverse of (c^a)' (mod p) BigInteger z = c.modPow(a, p).modInverse(p); BigInteger P = z.multiply(d).mod(p); byte[] plainTextArray = P.toByteArray(); return new String(plainTextArray); } }

    Read the article

  • what reverse proxy server will direct traffic to healthy servers whose health is based on a result string

    - by joshua paul
    what reverse proxy server will direct traffic to healthy servers whose health is based on a result string?? ideally i'd like something like dnsmadeeasy or ultradns - lol - but for reverse proxy i have looked at pound, delegate, ha proxy, squid, varnish, nginx, apache, and cherokee but can't see that they will work - they only test for HTTP result code scenario client request www.aaa.com www.aaa.com is a reverse proxy reverse proxy looks at "test.php" on server 1.aaa.com, 2.aaa.com and 3.aaa.com for result string "OK" if the server is "OK" then proxy requests to them help!

    Read the article

  • HowTo Crypt/Encrypt some string (e.g. Password) on Qt simple

    - by mosg
    Hi. Here what I have got: Qt SDK version 4.6.2 Windows XP Question: how can I simply crypt and encrypt simple QString value? I need this to be able to save some crypted string into the INI file, and after reopening application encrypt string to normal password string value. PS: I'm looking simple and nice solution. Thanks for help!

    Read the article

  • Json Convert To and From Query String with jquery?

    - by acidzombie24
    I have a string like a=6&id=99 (i might store it in html as 'a=6&id=99' however thats not what js will see). I would like to convert that string into an object so i can do func(o.a); or o.id=44; How do i do that? Part 2: How do i convert that object back to a query string? it would probably be trivial code that i can write.

    Read the article

  • How to populate List<string> with Datarow values from single columns...

    - by James
    Hi, I'm still learning (baby steps). Messing about with a function and hoping to find a tidier way to deal with my datatables. For the more commonly used tables throughout the life of the program, I'll dump them to datatables and query those instead. What I'm hoping to do is query the datatables for say column x = "this", and convert the values of column "y" directly to a List to return to the caller: private List<string> LookupColumnY(string hex) { List<string> stringlist = new List<string>(); DataRow[] rows = tblDataTable.Select("Columnx = '" + hex + "'", "Columny ASC"); foreach (DataRow row in rows) { stringlist.Add(row["Columny"].ToString()); } return stringlist; } Anyone know a slightly simpler method? I guess this is easy enough, but I'm wondering if I do enough of these if iterating via foreach loop won't be a performance hit. TIA!

    Read the article

  • My app has some basic problems, and it stops working

    - by user2882662
    I am writing a basic application which contains two activities. Both contain a TextView showing the title and the first one contains an EditText in which the user types a message and clicks on a button on its side, the second activity is launched which shows the message the user types. It has the following problems: The title (the first TextView in both the activities) doesn't show in the middle of the line, despite of the android:gravity="center_horizontal" attribute. The EditText in the first activity does not show at all. When I click on the button, the app stops saying "Unfortunately Write n Display and stopped.", rather than launching the second activity at all. I don't have adequate knowledge about logcat, but I have followed the steps somebody had told me, that is WindowOpen Perspective Other DDMS Then run the app and select the package name from the Devices and click on log cat, select the exception(s) and export to text file. All contained in the text file is : : E/(): Device disconnected: 1 Since I am not sure of using log cat, so I am posting a screenshot to make clear what I have done. CODE OF FIRST ACTIVITY: - package com.practice.myfirstapp1; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.EditText; //import android.view.Menu; public class MainActivity extends Activity { public static final String key_name="com.practice.firstApp.key"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } private void sendMessage(View view){ Intent intent= new Intent(this, SecondActivity.class); EditText editText=(EditText) findViewById(R.id.EditText1_MainActivity); String key_value= editText.getText().toString(); intent.putExtra(key_name, key_value); startActivity(intent); } } LAYOUT OF FIRST ACTIVITY: - <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" > <TextView android:id="@+id/TextView1_MainActivity" android:layout_alignParentTop="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+string/title_MainActivity" android:gravity="center_horizontal" android:textStyle="bold"/> <EditText android:id="@+id/EditText1_MainActivity" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_below="@+id/TextView1_MainActivity" android:hint="@string/EditText_MainActivity" android:textStyle="italic" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/TextView1_MainActivity" android:layout_toRightOf="@id/EditText1_MainActivity" android:text="@string/Button_MainActivity" android:onClick="sendMessage"/> </RelativeLayout> CODE OF SECOND ACTIVITY: - package com.practice.myfirstapp1; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.widget.TextView; class SecondActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); Intent intent= getIntent(); String intent_value= intent.getStringExtra(MainActivity.key_name); TextView textView= new TextView(this); textView= (TextView) findViewById(R.id.TextView2_SecondActivity); textView.setText(intent_value); } } LAYOUT OF SECOND ACTIVITY: - <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" tools:context=".SecondActivity"> <TextView android:layout_alignParentTop="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+string/title_SecondActivity" android:gravity="center_horizontal" android:textStyle="bold"/> <TextView android:id="@+id/TextView2_SecondActivity" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </RelativeLayout> STRINGS RESOURCE FILE:- <?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">Write n Display</string> <string name="action_settings">Settings</string> <string name="title_MainActivity">WRITE</string> <string name="EditText_MainActivity">Your Message here</string> <string name="Button_MainActivity">Send</string> <string name="title_SecondActivity">DISPLAY</string> </resources> ANDROID MANIFEST FILE: - <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.practice.myfirstapp1" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="18" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" android:debuggable="true" > <activity android:name="com.practice.myfirstapp1.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name="com.practive.myfirstapp1.SecondActivity" android:label="@string/app_name"> </activity> </application> </manifest>

    Read the article

  • Ruby on Rails: How to sanitize a string for SQL when not using find and other built-in methods?

    - by williamjones
    I'm trying to sanitize a string that involves user input without having to resort to manually crafting my own possibly buggy regex if possible. There are a number of methods in Rails that can allow you to enter in native SQL commands, how do people escape user input for those? The question I'm asking is a broad one, but in my particular case, I'm working with a column in my Postgres database that Rails does not natively understand as far as I know, the tsvector, which holds plain text search information. Rails is able to write and read from it as if it's a string, however, unlike a string, it doesn't seem to be automatically escaping it when I do things like vector= inside the model. For example, when I do model.name='::', where name is a string, it works fine. When I do model.vector='::' it errors out: ActiveRecord::StatementInvalid: PGError: ERROR: syntax error in tsvector: "::" "vectors" = E'::' WHERE "id" = 1 This seems to be a problem caused by lack of escaping of the semicolons, and I can manually set the vector='\:\:' fine. I also had the bright idea, maybe I can just call something like: ActiveRecord::Base.connection.execute "UPDATE medias SET vectors = ? WHERE id = 1", "::" However, this syntax doesn't work, because the raw SQL commands don't have access to find's method of escaping and inputting strings by using the ? mark. This strikes me as the same problem as calling connection.execute with any type of user input, as it all boils down to sanitizing the strings, but I can't seem to find any way to manually call Rails' SQL string sanitization methods. Can anyone provide any advice?

    Read the article

  • How do I match complete XML objects in a string?

    - by cyclotis04
    I'm attempting to find complete XML objects in a string. They have been placed in the string by an XmlSerializer, but may or may not be complete. I've toyed with the idea of using a regular expression, because it seems like the kind of thing they were built for, except for the fact that I'm trying to parse XML. I'm trying to find complete objects in the form: <?xml version="1.0"?> <type> <field>value</field> ... </type> My thought was a regex to find <?xml version="1.0"?><type> and </type>, but if a field has the same name as type, it obviously won't work. There's plenty of documentation on XML parsers, but they seem to all need a complete, fully-formed document to parse. My XML objects can be in a string surrounded by pretty much anything else (including other complete objects). hw<e>reR@lot$0fr@ndm&nchrs%<?xml version="1.0"?><type><field>...</field>...</type>@ndH#r$omOre!!>nuT6erjc?y!<?xml version="1.0"?><type><field>...</field>...</type>ty!=] A regex would be able to match a string while excluding the random characters, but not find a complete XML object. I'd like some way to extract an object, parse it with a serializer, then repeat until the string contains no more valid objects.

    Read the article

  • What is the query string of a BlazeDS request?

    - by dacracot
    I have a Tomcat service running on localhost:8080 and I have installed BlazeDS. I created and configured a simple hello world application like this... package com.adobe.remoteobjects; import java.util.Date; public class RemoteServiceHandler { public RemoteServiceHandler() { //This is required for the Blaze DS to instantiate the class } public String getResults(String name) { String result = “Hi ” + name + “, the time is : ” + new Date(); return result; } } With what query string can I invoke RemoteServiceHandler to my Tomcat instance via just a browser? Something like... http://localhost:8080/blazeds/?xyz

    Read the article

  • ASP.Net Error - Unable to cast object of type 'System.String' to type 'System.Data.DataTable'.

    - by xtrabits
    I get the below error Unable to cast object of type 'System.String' to type 'System.Data.DataTable'. This is the code I'm using Dim str As String = String.Empty If (Session("Brief") IsNot Nothing) Then Dim dt As DataTable = Session("Brief") If (dt.Rows.Count > 0) Then For Each dr As DataRow In dt.Rows If (str.Length > 0) Then str += "," str += dr("talentID").ToString() Next End If End If Return str Thanks

    Read the article

  • What's the best practice way to convert enum to string?

    - by dario
    Hi. I have enum like this: public enum ObectTypes { TypeOne, TypeTwo, TypeThree, ... TypeTwenty } then I need to convert this enum to string. Now Im doing this that way: public string ConvertToCustomTypeName(ObjectTypes typeObj) { string result = string.Empty; switch (typeObj) { case ObjectTypes.TypeOne: result = "This is type T123"; break; case ObjectTypes.TypeTwo: result = "This is type T234"; break; ... case ObjectTypes.TypeTwenty: result = "This is type last"; break; } return result; } Im quite sure that there is better way do do this, Im looking for some good practice solution. Thanks in advance.

    Read the article

  • Why empty String is treated as null in oracle?

    - by GK
    We are using empty string in DB2 database for some business logic. but when the same record tried to insert into the Oracle it throws some not null property references to null value error. that is oracle treats empty string as null. So i am wondering why it is like that. and if there is a requirement of storing empty string how to do that on oracle?

    Read the article

  • In OpenRasta, how do I configure a URI where I get "the remainder of the path" as a single string?

    - by Daniel Earwicker
    Normally in OpenRasta there is some configuration like this: ResourceSpace.Has.ResourcesOfType<Customers>() .AtUri("/customers/region/{region}") ... // and so on ... where the {region} part of the path is automatically mapped to a string parameter in the handling method. So if the user hits: http://server/customers/region/emea Then the handler method is passed the string "emea". As well as doing this, I'd like to register a handler with something like this: ResourceSpace.Has.ResourcesOfType<Customers>() .AtUri("/someotherthing/*") ... // and so on In this imaginary syntax, the asterisk would mean "take the rest of the path, including slashes, to be a single string parameter to pass to the handling method". And so if the user hits: http://server/someotherthing/how/about/this?that=other Then my handler method receives a string parameter: how/about/this?that=other Is such a thing possible in OpenRasta? In Sinatra (Ruby) I'd use a regular expression to do exactly this.

    Read the article

  • Objective-C - How To Remove Characters From a String?

    - by iAm
    I have a UILable that has a formatted String (formatted for currency), so there is a dollar sign, $21.34. In the core data entity the attribute is of a type double, I am using an NSDecimalNumber to save to the database. self.purchase.name = self.nameTextField.text; NSString *string = self.amountLabel.text NSDecimalNumber *newAmount = [[NSDecimalNumber alloc] initWithString:string]; NSLog(@"%@", string); // THIS RETURNS NaN, because of dollar sign i think NSManagedObjectContext *context = self.purchase.managedObjectContext; NSError *error = nil; if (![context save:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } Anyway, I need this to not be NaN, so my thinking is to remove the dollar sign, but i do not know how to do that, or perhaps there is a better way to accomplish my goal.

    Read the article

  • How to regex match a string of alnums and hyphens, but which doesn't begin or end with a hyphen?

    - by Shahar Evron
    I have some code validating a string of 1 to 32 characters, which may contain only alpha-numerics and hyphens ('-') but may not begin or end with a hyphen. I'm using PCRE regular expressions & PHP (albeit the PHP part is not really important in this case). Right now the pseudo-code looks like this: if (match("/^[\p{L}0-9][\p{L}0-9-]{0,31}$/u", string) and not match("/-$/", string)) print "success!" That is, I'm checking first that the string is of right contents, doesn't being with a '-' and is of the right length, and then I'm running another test to see that it doesn't end with a '-'. Any suggestions on merging this into a single PCRE regular expression? I've tried using look-ahead / look-behind assertions but couldn't get it to work.

    Read the article

  • Trying to use VB to automate some queries. Running into what looks like a string problem

    - by Jeff
    Hi there I'm using MS Access 2003 and I'm trying to execute a few queries at once using VB. When I write out the query in SQL it works fine, but when I try to do it in VB it asks me to "Enter Parameter Value" for DEPA, then DND (which are the first few letters of a two strings I have). Here's the code: Option Compare Database Public Sub RemoveDupelicateDepartments() Dim oldID As String Dim newID As String Dim sqlStatement As String oldID = "DND-01" newID = "DEPA-04" sqlStatement = "UPDATE [Clean student table] SET [HomeDepartment]=" & newID & " WHERE [HomeDepartment]=" & oldID & ";" DoCmd.RunSQL sqlStatement & "" End Sub It looks to me as though it's taking in the string up to the - then nothing else. I dunno, that's why I'm asking lol. What should my code look like?

    Read the article

  • How do I store a string longer than 4000 characters in an Oracle Database using Java/JDBC?

    - by Ventrue
    I’m not sure how to use Java/JDBC to insert a very long string into an Oracle database. I have a String which is greater than 4000 characters, lets say it’s 6000. I want to take this string and store it in an Oracle database. The way to do this seems to be with the CLOB datatype. Okay, so I declared the column as description CLOB. Now, when it comes time to actually insert the data, I have a prepared statement pstmt. It looks like pstmt = conn.prepareStatement(“INSERT INTO Table VALUES(?)”). So I want to use the method pstmt.setClob(). However, I don’t know how to create a Clob object with my String in it; there’s no constructor (presumably because it can be potentially much larger than available memory). How do I put my String into a Clob? Keep in mind I’m not a very experienced programmer; please try to keep the explanations as simple as possible. Efficiency, good practices, etc. are not a concern here, I just want the absolute easiest solution. I’d like to avoid downloading other packages if it all possible; right now I’m just using JDK 1.4 and what is labelled “ojdbc14.jar”. I've looked around a bit but I haven't been able to follow any of the explanations I've found. If you have a solution that doesn’t use Clobs, I’d be open to that as well, but it has to be one column.

    Read the article

  • Read VB binary file with c# (knowing the structure)

    - by Kai
    I'd like to read a file that has been binary saved by a vb prog. the file should be read line by line, 'cause every single line represents an object with many attributes. a link looks the following: 999011011/10/1 ELW the structure of data types is: Public Type FahrzeugDAT Kennung As String * 8 Name As String * 30 Info As String * 50 StatusFzg As Integer DatumFzg As Date StatusLst As Integer DatumLst As Date TKI As Integer Folgetlg As Integer LstKurztext As String * 100 FME1 As String * 5 FME2 As String * 5 FME3 As String * 5 DME1 As String * 8 DME2 As String * 8 DME3 As String * 8 Bemerkung As String * 256 Art As Long Standort As Long End Type

    Read the article

< Previous Page | 214 215 216 217 218 219 220 221 222 223 224 225  | Next Page >