Question

Java: convert string to integer

Answer 1

Converting a string to the data type int
Convert a string to an integer object

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Wondering how to convert a string to int? Our step-by-step guide shows you how to do it!

In Java there are a large number of inputs and values ​​that have to be converted into an integer in order to produce an output. If you want to convert a string (i.e. a variable in which a character string is stored) into an integer, take a look at our instructions.

There are two options for this process:

• Converting a string to the data type int
• Convert a string to an integer object

Converting a string to the data type int

You use the static method for this form of conversion Integer.parseInt(String s) . ParseInt returns a simple int entity. The string may only consist of digits and only contain a plus or minus sign at the beginning.

Example:

Integer.parseInt (“10“); Integer.parseInt (“+ 10“); Integer.parseInt (“10.5“); Integer.parseInt (“10“);

// correct // correct // error, period is not allowed // error, spaces are not allowed

Integer.parseInt(“10“); Integer.parseInt(“+10“); Integer.parseInt(“10.5“); Integer.parseInt(“ 10“);

//korrekt //korrekt //Fehler, Punkt ist nicht erlaubt //Fehler, Leerzeichen sind nicht erlaubt

If a string contains illegal characters, an exception is thrown. There are no spaces , separators , points or commas allowed..

Convert a string to an integer object

For this conversion you use the static mathode Integer.valueOf(String s ). A static method is a method that has a class definition .
A new instance of is java.lang.integer returned.

Example:

Integer i = Integer.valueOf (“10“);

Integer i = Integer.valueOf(“10“);

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