Different ways for String to Integer Conversions in Java
Examples:
Input: str = "1234" Output: 1234 Input: str = "456" Output: 456
- Convert using Integer.parseInt(String)
The Integer class has a static method that returns an integer object representing the specified String parameter.
Syntax :public static int parseInt(String str) throws NumberFormatException or public static int parseInt(String str, int radix) throws NumberFormatException
Parameters:
- str: A string which needs to be converted to the integer. It can also have the first character as a minus sign ‘-‘ (‘\u002D’) or plus sign ‘+’ (‘\u002B’) to represent the sign of the number.
- radix: The radix used while the string is being parsed. This parameter is only specific to the second variant of the method.
Exceptions: NumberFormatException is thrown by this method if any of the following situations occurs:
For both the variants:
- String is null or of zero length
- The value represented by the string is not a value of type int
- Specifically for the parseInt(String s, int radix) variant of the function:
- The second argument radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX
- Any character of the string is not a digit of the specified radix, except that the first character may be a minus sign ‘-‘ (‘\u002D’) or plus sign ‘+’ (‘\u002B’) provided that the string is longer than length 1
Example:
class
GfG {
public
static
void
main(String args[])
{
String str =
"1234"
;
int
num1 = Integer.parseInt(str);
System.out.println(
"Integer using "
+
"first variant of"
+
" praseInt = "
+ num1);
int
num2 = Integer.parseInt(str,
16
);
System.out.println(
"Integer using "
+
"second (radix) variant"
+
" of praseInt = "
+ num2);
}
}
Output:Integer using first variant of praseInt = 1234 Integer using second (radix) variant of praseInt = 4660
- Convert using Integer.valueOf(String)
Syntax:
public static Integer valueOf(String str)
Parameters: This method accepts single parameter str of String type that is to be parsed.
Return Value: The method returns an Integer object holding the value represented by the string argument.
Example:
class
GfG {
public
static
void
main(String args[])
{
String str =
"1234"
;
int
num1 = Integer.valueOf(str);
System.out.println(
"Integer using"
+
" valueOf() = "
+ num1);
}
}
Output:Integer using valueOf() = 1234
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