Converting a string to int in Groovy

Question

I have a String that represents an integer value and would like to convert it to an int. Is there a groovy equivalent of Java's Integer.parseInt(String)?

Answer 1

The way to use should still be the toInteger(), because it is not really deprecated.

int value = '99'.toInteger()

The String version is deprecated, but the CharSequence is an Interface that a String implements. So, using a String is ok, because your code will still works even when the method will only work with CharSequence. Same goes for isInteger()

See this question for reference : How to convert a String to CharSequence?

I commented, because the notion of deprecated on this method got me confuse and I want to avoid that for other people.

Answer 2

Use the toInteger() method to convert a String to an Integer, e.g.

int value = "99".toInteger()

An alternative, which avoids using a deprecated method (see below) is

int value = "66" as Integer

If you need to check whether the String can be converted before performing the conversion, use

String number = "66"

if (number.isInteger()) {
  int value = number as Integer
}

Deprecation Update

In recent versions of Groovy one of the toInteger() methods has been deprecated. The following is taken from org.codehaus.groovy.runtime.StringGroovyMethods in Groovy 2.4.4

/**
 * Parse a CharSequence into an Integer
 *
 * @param self a CharSequence
 * @return an Integer
 * @since 1.8.2
 */
public static Integer toInteger(CharSequence self) {
    return Integer.valueOf(self.toString().trim());
}

/**
 * @deprecated Use the CharSequence version
 * @see #toInteger(CharSequence)
 */
@Deprecated
public static Integer toInteger(String self) {
    return toInteger((CharSequence) self);
}

You can force the non-deprecated version of the method to be called using something awful like:

int num = ((CharSequence) "66").toInteger()

Personally, I much prefer:

int num = 66 as Integer

Answer 3

I'm not sure if it was introduced in recent versions of groovy (initial answer is fairly old), but now you can use:

def num = mystring?.isInteger() ? mystring.toInteger() : null

or

def num = mystring?.isFloat() ? mystring.toFloat() : null

I recommend using floats or even doubles instead of integers in the case if the provided string is unreliable.

Answer 4

def str = "32"

int num = str as Integer

Answer 5

The Simpler Way Of Converting A String To Integer In Groovy Is As Follows...

String aa="25"
int i= aa.toInteger()

Now "i" Holds The Integer Value.

Answer 6

Here is the an other way. if you don't like exceptions.

def strnumber = "100"
def intValue = strnumber.isInteger() ?  (strnumber as int) : null

Answer 7

Several ways to achieve this. Examples are as below

a. return "22".toInteger()
b. if("22".isInteger()) return "22".toInteger()
c. return "22" as Integer()
d. return Integer.parseInt("22")

Hope this helps

Answer 8

Groovy Style conversion:

Integer num = '589' as Integer

If you have request parameter:

Integer age = params.int('age')

Answer 9

toInteger() method is available in groovy, you could use that.

Answer 10

also you can make static import

import static java.lang.Integer.parseInt as asInteger

and after this use

String s = "99"
asInteger(s)

Answer 11

As an addendum to Don's answer, not only does groovy add a .toInteger() method to Strings, it also adds toBigDecimal(), toBigInteger(), toBoolean(), toCharacter(), toDouble(), toFloat(), toList(), and toLong().

In the same vein, groovy also adds is* eqivalents to all of those that return true if the String in question can be parsed into the format in question.

The relevant GDK page is here.

Answer 12

Several ways to do it, this one's my favorite:

def number = '123' as int

Answer 13

Well, Groovy accepts the Java form just fine. If you are asking if there is a Groovier way, there is a way to go to Integer.

Both are shown here:

String s = "99"
assert 99 == Integer.parseInt(s)
Integer i = s as Integer
assert 99 == i