Backspace character java

Error: You don't have JavaScript enabled. This tool uses JavaScript and much of it will not work correctly without it enabled. Please turn JavaScript back on and reload this page. Please enter a title. You can not post a blank message. Please type your message and try again. This discussion is archived. I have a text area with a document listener below. When a user types into it, the input is saved into the string userInput, and the text is then removed from the text area so it is not displayed using invokeLater.

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I need the Backspace key to do what it is supposed to do, remove the last character from the userInput string, but I don't know how to do that. Please help, Thanks typedArea. This content has been marked as final. Show 9 replies.

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That's what you get for trying to be too clever And what about navigating - say user wants to go back a few characters and insert something? At this point you should stop and reconsider your current approach of using a text area for input, while wanting to remove the actual contents.

Have any ideas as to how to incorporate that. The main thing is that the user must not see what they are typing. Also, if I use a keyListener as well, how would I remove the last character from a String? And btw, what is the key code for Backspace? I didnt see it under keyevent stuff.Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.

Most of the time, if you are using a single character value, you will use the primitive char type. For example:. The Java programming language provides a wrapper class that "wraps" the char in a Character object for this purpose. An object of type Character contains a single field, whose type is char. This Character class also offers a number of useful class i. The Java compiler will also create a Character object for you under some circumstances. For example, if you pass a primitive char into a method that expects an object, the compiler automatically converts the char to a Character for you.

For more information on autoboxing and unboxing, see Autoboxing and Unboxing. The following table lists some of the most useful methods in the Character class, but is not exhaustive. For a complete listing of all methods in this class there are more than 50refer to the java.

Character API specification. The following table shows the Java escape sequences:. When an escape sequence is encountered in a print statement, the compiler interprets it accordingly. To print the sentence. All rights reserved. Hide TOC. Numbers and Strings.Get char at 2. String big 3.

String blink 4. Make string bold 5. Create anchor from a string 6. Get char Code 7. Concat String 8. String escape 9.

Escape double quote Including a special character in a string String font Color String font Size String index Of Combine indexOf and substring methods to get the anchor part of a url Search the string and counts the number of e's String from Char Code String in italics String last Index Of String length Compare string in locale format Make String link Match string String replace Slice a string Get small String Split a string Return strike String String sub Example Get sub string substr Use substring method to get the sub string Get super script sup Get Lower case String toLowerCase Get Upper Case string toUpperCase Check the first letter of a name Use String.

Validate a time value input with string. Return string value from a function Tab string character Adding trim function to String Double quote string character Many classes allow inclusion of escape sequences in character and string literals; examples include java. Correct use of escape sequences in string literals requires understanding how the escape sequences are interpreted by the Java compiler as well as how they are interpreted by any subsequent processor, such as a SQL engine.

When representing SQL statements in Java string literals, each escape sequence must be preceded by an extra backslash for correct interpretation. As another example, consider the Pattern class used in performing regular expression-related tasks. A string literal used for pattern matching is compiled into an instance of the Pattern type.

The string constructed from the resulting sequence. This noncompliant code example defines a method, splitWordsthat finds matches between the string literal WORDS and the input sequence. This compliant solution shows the correctly escaped value of the string literal WORDS that results in a regular expression designed to split on word boundaries:.

This noncompliant code example uses the same method, splitWords. This is read by the Properties. Although the string is interpreted differently than if it were a string literal, as in the previous noncompliant code example, the interpretation is incorrect. Incorrect use of escape characters in string inputs can result in misinterpretation and potential corruption of data. So we need a different example in the intro.

When representing SQL queries in Java string form, all escape sequences must be preceded by an extra backslash for correct interpretation. SQl statements are actually not written out that way. The usual method is to read individual queries from a properties file key-value pair. The string constructed from the resulting sequence. On first read the conclusion appears to contradict the introductory statement. Isn't that easier to understand? They more certainly are. Perhaps it would help to reword to "and correctly denotes a newline character in the pattern for the purpose of matching with an input string".

That is the specific advice on fixing the NCCE. The guidline is trying to be more general and focus on why you need two backslashes. Can we have another NCCE that isn't solved by adding a second backslash?

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Perhaps just a description of such an example is enough. I am just going to answer 1 for now: I think that the SQL query sentence is a bit unclear which led to the confusion I haven't seen any escape sequence in any SQL queries in two years. The example link you provided exemplifies how escape characters can be used from the MySql command line to format text for the command line. A better example I can think of is - if an application wants to save formatted user input into the DB such as to preserve newlines then it may expect escape sequences.

We should cite such an example otherwise the sentence sounds a bit confusing and open to reader interpretation.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

backspace character java

Java doesn't 'handle' that character at all. All it knows about is a byte stream onto which the OS says it can write bytes, and it will happily write bytes into it, including an ASCII backspace.

What happens when the stream receives that character has nothing whatsoever to do with Java, it is totally terminal-dependent.

Some terminals will erase the previous character, some will display the backspace character as some weird glyph, or even as a special "backspace character" glyph.

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Some may drop the character altogether if they can't interpret it, others most terminal emulators, in fact will behave differently depending on how they're configured. To get your desired Output i. All you can do is replace the character to be deleted by space.

Thus try the following line to get Hell as output :. For other OS it may behave differently as explained by Kilian Foth above. It should work perfectly fine in Windows command console.

This bug is recognizeable as an Eclipse bug: bug However, if you run them in terminal, it could be executed.

backspace character java

All the terminals have that library. Learn more. Java backspace escape Ask Question. Asked 9 years, 8 months ago. Active 1 year, 8 months ago. Viewed 30k times. I just tested the backspace escape as follows: System.In addition, this class provides several methods for determining a character's category lowercase letter, digit, etc.

Character information is based on the Unicode Standard, version 6. The methods and data of class Character are defined by the information in the UnicodeData file that is part of the Unicode Character Database maintained by the Unicode Consortium. This file specifies various properties including name and general category for every defined Unicode code point or character range. The Unicode Standard has since been changed to allow for characters whose representation requires more than 16 bits.

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An int value represents all Unicode code points, including supplementary code points. The lower least significant 21 bits of int are used to represent Unicode code points and the upper most significant 11 bits must be zero.

backspace character java

Unless otherwise specified, the behavior with respect to supplementary characters and surrogate char values is as follows: The methods that only accept a char value cannot support supplementary characters. They treat char values from the surrogate ranges as undefined characters.

For example, Character. The methods that accept an int value support all Unicode characters, including supplementary characters. For more information on Unicode terminology, refer to the Unicode Glossary. Since: 1. Subset Instances of this class represent particular subsets of the Unicode character set.

UnicodeBlock A family of character subsets representing the character blocks in the Unicode specification. Replaced by isJavaIdentifierStart char. Replaced by isJavaIdentifierPart char. Replaced by isWhitespace char.

backspace character java

String toString Returns a String object representing this Character 's value. The constant value of this field is the smallest value permitted for the radix argument in radix-conversion methods such as the digit method, the forDigit method, and the toString method of class Integer.If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.

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Java.lang.Character.isWhitespace() Method

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment? Please use ide. String after processing backspace characters Queries to find the left-most given type integer in a binary array Sum and product of K smallest and largest Fibonacci numbers in the array Word Ladder - Set 2 Bi-directional BFS Minimum cost to reach from the top-left to the bottom-right corner of a matrix Length of Smallest Subsequence such that sum of elements is greater than equal to K Print all Palindromic Levels Of a Binary Tree Minimize the maximum difference between adjacent elements in an array.

Java.lang.Character.isWhitespace() Method

Python3 implementation of above approach. Function to find new final String. Build final string.


Function call to print. This code is contributed by Rituraj Jain. Push S[i]. Pop. WriteLine newString S. Check out this Author's contributed articles. Load Comments.

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