I try to make a string pattern that can contain UTF-8 characters (öäå, etc) and match the following criteria in Java (1.7); Must start with # or @ Must be lower-case Can contain – or _ (minus and …
Tag: string
Calling equals on string literal
I just was tidying my code a bit and there was this piece: Then I thought of doing it the other way around to get rid of the checking for null: It definitely works, but is this safe to do so? I mean string literals are stored in a common pool, while string object create by new are on the
Delete anything between “<” and “>” in a String
I have try restString = restString.replaceAll(“\<.*\>”, “”); and restString = restString.replaceAll(“\<[^(\>)]*\>”, “”);. Both seems don’t work. I don’t know if I could represent the meaning in the regular expression…
Finding second occurrence of a substring in a string in Java
We are given a string, say, “itiswhatitis” and a substring, say, “is”. I need to find the index of ‘i’ when the string “is” occurs a second time in the original string. String.indexOf(“is”) will return 2 in this case. I want the output to be 10 in th…
Scanner needs/is requesting input twice
I’m just writing a small program that receives input from the user then prints it back to them. However, when I run the program it asks for input twice (it prints the initial statement, then once you type and press enter, nothing happens, but if you do it again it works and prints.) The top value appare…
How to sort an array of objects in Java?
My array does not contain any string. But its contains object references. Every object reference returns name, id, author and publisher by toString method. Now I need to sort that array of objects by the name. I know how to sort, but I do not know how to extract the name from the objects and sort them. Answer…
How can I prevent java.lang.NumberFormatException: For input string: “N/A”?
While running my code I am getting a NumberFormatException: How can I prevent this exception from occurring? Answer “N/A” is not an integer. It must throw NumberFormatException if you try to parse it to an integer. Check before parsing or handle Exception properly. Exception Handling or – In…
Check and extract a number from a String in Java
I’m writing a program where the user enters a String in the following format: I need to check that there is a number in the String and then extract just the number. If i use .contains(“\d+”) or .contains(“[0-9]+”), the program can’t find a number in the String, no matter wh…
Formatting a string array in java
I have a string array which has k elements. I want to print them out using System.out.format, but the issue is that I do not know k. So essentially, I want to use something like: System.out.format(“%s %s … k times”, str1, str2, … strk); (where k is a variable) I was looking through the…
Print out elements from an Array with a Comma between the elements
I am printing out elements from an ArrayList and want to have a comma after each word except the last word. Right now, I am doing it like this: It prints out the words like this: The problem is the last comma. How do I solve it? Answer Print the first word on its own if it exists. Then print