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);

Solution 1

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.

Solution 2

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

Solution 3

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);

Solution 4

String s = "1";

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

Solution 5

You can also try following,

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

View more solutions

Comments

[Admin]

Thank you. i got stuck on lg.getLong as per link

[Cristian]

getLong returns a long from a system property. That's why it does not work as you expected.

[Alex Punnen]

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

[Debosmit Ray]

Could you also add why you think this is better than simply calling parseLong()?