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I would like to compare two numeric string such as "1.0.1" and "2.1.1". May I know that is there any string utility method in Java to compare or need to implement like remove .(dot), parse to integer and compare manually? Thank you.

BomberBus
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  • How will you parse "1.0.1" as a number? its got 2 decimal points... – Rohan Feb 18 '16 at 04:23
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    @Bus Car, As per I know there is no single utility method to solve you purpose. You need to implement as you told. – mmuzahid Feb 18 '16 at 04:30
  • Looks like duplicate for Version Comparision: [http://stackoverflow.com/questions/198431/how-do-you-compare-two-version-strings-in-java](http://stackoverflow.com/questions/198431/how-do-you-compare-two-version-strings-in-java) – LChukka Feb 18 '16 at 04:32
  • @BusCar - Whichever answer has helped you, kindly upvote and accept the answer. It is a very bad habit to leave the question marked as unresolved. Else, from the next time experts would prevent answering your question! Good Luck, :) – Am_I_Helpful Feb 22 '16 at 06:36

4 Answers4

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remove .(dot)

myString.replaceAll("\\.","")

parse to integer

int myInt = Integer.parseInt(myString);

compare manually

if(myInt < myInt2) { // ....
phil294
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You can use String.replaceAll(String regex, String replacement) to replace all the dots with an empty string.

String str1 = "1.0.1";
str1 = str1.replaceAll(".","");
int num1 = Integer.parseInt(str1);
// similarly for num2
String str2 = "2.1.2";
str2 = str2.replaceAll(".","");
int num2 = Integer.parseInt(str2);
if (num1 == num2)
// do Something
else
// do Something else.
Dave
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Am_I_Helpful
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  • remember that strings are immutable in Java so the String.replace() method will return the new string, not just simplify modify the original. try: str1 = str1.replaceAll(".",""); and the same for str2 – Dave Feb 18 '16 at 06:15
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    @Dave - Oh, Thanks. I forget assigning the new string to original string reference. I was doing 2 works at the same time, :D – Am_I_Helpful Feb 18 '16 at 06:38
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You can use mystr.replace('.', '') and compare using mystr.equals(mystr2). Or to compare the strings as number you could parse to Integer, like so:

myInt = Integer.parseInt(mystr);
if(myInt == myInt2) {
   // do something
}
Sнаđошƒаӽ
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Split the strings on the dot (string.split("\\.") — you have to escape the . since split takes a regex, and you have to escape the escape because you're typing it as a Java string literal), and then parse and compare each component from the two strings. As you do so, if the components are unequal, there's your answer; otherwise, go on to the next one. If there isn't a next one, the two strings are equal.

For instance, given "1.2.3" and "1.4.5", the splits would be ["1", "2", "3"] and ["1", "4", "5"]. So you'd first parse and compare the strings at index 0; they're both 1, so you go to the next index. Then you parse and compare the strings at index 1; 2 < 3, so "1.2.3" < "1.4.5".

Depending on your use case, you may also need to cover use cases like if they have different number of components (for instance, "1.2.3" vs "1.2").

Do not just remove the dot, as other answers have said, unless you want 2.3.4 to be lower than 1.23.4, since 234 < 1234.

yshavit
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