How do one convert a big int to a string (or integer) in Golang?
bigint := big.NewInt(123) //This is what I have
bigstr = "123" //This is what I want
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2Thanks for the comment pst. After hours of searching, I would say that the documentation is not great on bigints. For instance, I still couldn't figure out for the life of me how to convert from a string to a bigint.Yster– Yster2012-08-04 23:20:56 +00:00Commented Aug 4, 2012 at 23:20
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3 Answers
Just use the String method : http://golang.org/pkg/math/big/#Int.String
bigint := big.NewInt(123)
bigstr := bigint.String()
2 Comments
Yster
Thanks for the answer, cyberdelia. Should I make a new question, or can I ask you how to convert the other way around: from a string to a bigint? (Again, I couldn't find the answer anywhere).
Yster
@BurntSushi5 - Thank you so much! That is a great little string to big.Int example: bigint.SetString("123", 10)
You asked how to convert a bigInt to string or to int, the accepted answer explains only how to convert to string.
So you have your bigint := big.NewInt(123)
You can convert your bigInt to integer in two possible ways:
The reason for two methods is that uint holds 2 time bigger numbers, and sometimes you know that the answer is positive. Beware that if the number is bigger than the maximum possible for int64/uint64:
If x cannot be represented in an int64, the result is undefined.
And for completeness, to convert to string, just use .String() bigstr := bigint.String()
Comments
I used the following:
bigint := big.NewInt(1231231231231)
bigstr := fmt.Sprint(bigint)
2 Comments
Dave C
Calling
bigint.String() directly (instead of via interface{} of fmt) is simpler and more efficient. The only reason to use the fmt package for this is if you wanted to make use of special formatting.
victorsamuelmd
I used the bigint.String() in a really big int and obtained something like 1.2123423534546e308