How to convert string to long

Question

how do you convert a string into a long.

for int you

int i = 3423;
String str;
str = str.valueOf(i);

so how do you go the other way but with long.

long lg;
String Str = "1333073704000"
lg = lg.valueOf(Str);

This is a duplicate of question: http://stackoverflow.com/a/2709269/108574 — He Shiming, Mar 30 '12 at 06:33

score 180 · Accepted Answer · answered Mar 30 '12 at 03:32

180

This is a common way to do it:

long l = Long.parseLong(str);

There is also this method: Long.valueOf(str); Difference is that parseLong returns a primitive long while valueOf returns a new Long() object.

answered Mar 30 '12 at 03:32

Cristian

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Thank you. i got stuck on lg.getLong as per [link](http://developer.android.com/reference/java/lang/Long.html#getLong(java.lang.String)) – Mar 30 '12 at 03:43
`getLong` returns a long from a system property. That's why it does not work as you expected. – Cristian Mar 30 '12 at 03:48
It is easy to make the mistake of assuming the input string is in the form you expect ; "90.77" will throw ParseException with this. So dont ignore the ParseException, but handle it for your use case – Alex Punnen Apr 23 '14 at 06:58

score 9 · Answer 2 · answered Mar 30 '12 at 03:33

9

The method for converting a string to a long is Long.parseLong. Modifying your example:

String s = "1333073704000";
long l = Long.parseLong(s);
// Now l = 1333073704000

answered Mar 30 '12 at 03:33

Adam Mihalcin

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score 6 · Answer 3 · edited Apr 04 '16 at 22:14

6

IF your input is String then I recommend you to store the String into a double and then convert the double to the long.

String str = "123.45";
Double  a = Double.parseDouble(str);

long b = Math.round(a);

edited Apr 04 '16 at 22:14

thor

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answered Apr 04 '16 at 22:04

Bijay Dhital

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Could you also add why you think this is better than simply calling `parseLong()`? – Debosmit Ray Apr 04 '16 at 22:17

score 5 · Answer 4 · answered Jun 19 '14 at 14:55

5

String s = "1";

try {
   long l = Long.parseLong(s);       
} catch (NumberFormatException e) {
   System.out.println("NumberFormatException: " + e.getMessage());
}

answered Jun 19 '14 at 14:55

borchvm

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score 2 · Answer 5 · edited Sep 21 '15 at 12:20

2

import org.apache.commons.lang.math.NumberUtils;

This will handle null

NumberUtils.createLong(String)

edited Sep 21 '15 at 12:20

Slyvain

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answered Sep 21 '15 at 11:57

lalitesh singh

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score 2 · Answer 6 · edited Apr 19 '16 at 01:03

2

Use parseLong(), e.g.:

long lg = lg.parseLong("123456789123456789");

edited Apr 19 '16 at 01:03

Mogsdad

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answered Apr 18 '16 at 22:17

Kazem Maleki

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score 2 · Answer 7 · answered Mar 30 '12 at 03:34

2

You can also try following,

long lg;
String Str = "1333073704000"
lg = Long.parseLong(Str);

answered Mar 30 '12 at 03:34

Lucifer

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score 1 · Answer 8 · answered Jul 11 '14 at 09:58

Do this:

long l = Long.parseLong(str);

However, always check that str contains digits to prevent throwing exceptions. For instance:

String str="ABCDE";
long l = Long.parseLong(str);

would throw an exception but this

String str="1234567";
long l = Long.parseLong(str);

won't.

How to convert string to long

8 Answers8

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