Home » StringBuilder delete methods [closed]

StringBuilder delete methods [closed]

Solutons:


I’d say this is fine. The intent is different.

Lets try this for example:

String builder sb = new StringBuilder();
sb.append("hello").append("hello");
sb.delete(0,5);
sb.toString();

It prints "hello".

Had you read the documentation, you’d see that the end is non-inclusive, meaning it will delete from start to end-1, hence no IndexOutOfBounds.

However, try this:

StringBuilder builder = new StringBuilder();

builder.append("hello");
builder.delete(0,7);

and you will most likely get an index out of bounds.

EDIT:
Personal gripe – it’s a fine balance between stopping someone from shooting themselves in the foot by throwing an exception, and just letting them do it but actually doing nothing in that case.

One example of “you really can’t do this, and will get an exception” is e.g. calling init() twice on something important that should really be initialized only once.

One example of “You shouldn’t do this, but I won’t crash your program if you do” is e.g. calling init() twice on a logger.

In this particular case, trying to delete a character that is out of bounds, falls into the first category. So that “it’s your bug, not mine” kinda thing.

But deleting a range – personally – shouldn’t even throw an exception. If the range is bigger than the length of the string, it’s my thing’s job to delete everything (in the range you specified), and it’s your bug to figure out why you deleted more than you did.

And this is exactly the kind of thing that demonstrates why writing documentation is important.

So that if you did this:

String builder sb = new StringBuilder();
sb.append("hello").append("Jello");
sb.delete(0,6); //e.g. you somehow thought that hello is of length 6
sb.toString();

and get a Jello it’s your thing to figure out why. Your bug. Not mine.
if you did sb.delete(0,7); and get a ello, it’s your thing to figure out why. Your bug, not mine. The docs are clear on what will happen.

But it depends on what the “thing” is. If it’s important, nope, you’ll get an exception. If it’s something stupid, sure, go ahead, shoot yourself in the foot, harmlessly.

However, in this particular case, i’d allow even this code to work fine:

String builder sb = new StringBuilder();
sb.append("hello").append("hello");
sb.delete(0,200);
sb.toString();

and not throw an exception. But internally, i’d only do delete(0,10)

TL;DR – it’s not inconsistent, it’s working exactly like it says it works.

Related Solutions

What are the available Signals in Java

Eventually I brute forced the single to 5 character length signals and got these: BREAK (21) SEGV (11) ILL (4) FPE (8) TERM (15) ABRT (22) INT (2) The code: Set<String> signals = new HashSet<>(); String currentSignalStr; for (char i = 'A'; i <=...

Understanding unique keys for array children in React.js

You should add a key to each child as well as each element inside children. This way React can handle the minimal DOM change. In your code, each <TableRowItem key={item.id} data={item} columns={columnNames}/> is trying to render some children inside them...

most efficient AABB vs Ray collision algorithms

Andrew Woo, who along with John Amanatides developed the raymarching algorithm (DDA) used ubiquitously in raytracers, wrote "Fast Ray-Box Intersection" (alternative source here) which was published in Graphics Gems, 1990, pp. 395-396. Rather than being built...

What is the difference between #!/bin/sh and #!/bin/bash?

bash and sh are two different shells. Basically bash is sh, with more features and better syntax. Most commands work the same, but they are different. Having said that, you should realize /bin/sh on most systems will be a symbolic link and will not invoke sh....

How to pass password to mysql command line

The mysql client utility can take a password on the command line with either the -p or --password= options. If you use -p, there must not be any blank space after the option letter: $ mysql -pmypassword I prefer the long options in scripts as they are...

how to leave a gap in select list from left [closed]

Maybe you were after something like: <select style="padding: 0 0 0 10px"> <option>Male</option> <option>female</option> <option>other</option> </select> jsFiddle example here. Is that what you wanted? Edit: After...

How to use multiple condition in one foreach loop?

Use two loops: foreach ($products as $product) { foreach ($categories as $category) { // using $product and $category } } I had the same question today as the OP. I figured I can split up the problem by first merging the two arrays and then performing the...

Why do Primitive Data Types have a Fixed Size?

As low-level programming languages, the designs of C and C++ closely follow what common hardware is capable of. The primitive building blocks (fundamental types) correspond to entities that common CPUs natively support. CPUs typically can handle bytes and words...

how do i count the words in a string list

Shouldn't it be string[] words = s.Split(' '); Even if we say your word is s.Split(' '); then it should be string[] words = word not string[]=word And to count how much words are in that array just do int howManyWords = words.Length; Also if you want to go...

Data from text file to dataframe

Here you go! It's really fast. For a file with ~11 million lines (made by copying and pasting your sample file over and over again), it took about 22 seconds on my machine, and produced a dataframe with 2.2 million rows. Note: I wasn't sure quite how to handle...

Unexpected output when creating a List of Lists in Java

You are adding all the integers to the same inner list (the one that you create at the start of your method with the statement List<Integer> l1 = new ArrayList<Integer>();). You should create a new List before adding elements to it: for(int i=1;...

how to calculation cost time [closed]

I think I understand what you're asking. You just want to have a new dataframe that calculates the time difference between the three different entries for each unique order id? So, I start by creating the dataframe: data = [...

how to disable button on change using jquery

you can do this as am assuming a image and am checking the resolutions and then i disable or enable the button as per requirements and also am clearing selected image so user can't upload the wrong format . <script> var _URL = window.URL ||...

Detect and uninstall antivirus

You could try the following, from https://community.spiceworks.com/scripts/show/3161-detect-and-remove-software-powershell: ################################################ # Powershell Detect and Remove software script # # # # V1.0 - Gav #...

return statement in c ??? why this function always returning 20?

You have a problem in your code. Change scanf("%d",arr[i]); To scanf("%d",&arr[i]); This is done because scanf expects an argument of type int* but you provide argument arr[i] which is of type int. Also add a check that ends the program if user inputs a...

How to add Bootstrap? [closed]

By adding the CDN <html> <head> <title>Cube</title> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script> <!-- Latest compiled and minified CSS --> <link rel="stylesheet"...