Discussing the problem of precision loss in Golang

Golang is a strongly typed language. When dealing with floating point numbers, you will encounter the problem of precision loss. This article will discuss the problem of precision loss in Golang from the following aspects:

1. What is precision loss in Golang

When using Golang to process floating point numbers, Due to the computer's internal representation, the representation of decimals is not necessarily accurate. For example, the binary representation of 0.1 is 0.00011001100110011001100..., which can only save a certain number of decimal places when represented internally by the computer. This leads to the fact that when performing a series of floating-point calculations, the accuracy of decimals may be affected, resulting in the problem of loss of accuracy.

2. Precision Loss Example in Golang

Let’s see an example:

a := 0.1
b := 0.2
c := a + b
fmt.Println(c)

// 输出：0.30000000000000004

In this example, we want to add 0.1 and 0.2 , get 0.3. But when we run the program, we find that the result becomes an approximate decimal of 0.30000000000000004. This is because Golang uses the IEEE 754 standard and uses binary to represent floating point numbers. However, binary cannot accurately represent decimals such as 0.1 and 0.2, which will lead to accumulation of errors.

3. How to avoid precision loss in Golang

To avoid the precision loss problem in Golang, we can use some tricks and libraries.

First of all, we can use the Decimal type instead of the default float64. go-lang-Decimal is a high-precision decimal calculation library that uses strings to represent floating-point numbers, thereby avoiding the problem of loss of precision in binary floating-point numbers. The following is an example of using the go-lang-Decimal library:

a, _ := decimal.NewFromString("0.1")
b, _ := decimal.NewFromString("0.2")
c := a.Add(b)
fmt.Println(c)

// 输出：0.3

In addition to the Decimal type, we can also use the Rat type in the math/big package to perform fractional operations. Rat type is a fraction type that can ensure the accuracy of decimals. The following is an example of using the Rat type:

a := big.NewRat(1, 10)
b := big.NewRat(2, 10)
c := big.NewRat(0, 1)
c.Add(a, b)
fmt.Println(c.FloatString(1))

// 输出：0.3

In addition, we can also use some high-precision calculation libraries, such as go-math-big, go-floating-point, etc.

Summary

The problem of precision loss in Golang is an unavoidable problem, but we can use some techniques and libraries to avoid this problem. Although these solutions may increase some development costs, they can provide us with more reliable calculation results.

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