golang floating point to integer

Golang is a high-performance programming language that supports multiple data types, including floating point numbers and integers. In actual development, we sometimes need to convert floating point numbers into integers for some calculations and processing. This article will introduce the methods and techniques of converting floating point numbers to integers in Golang.

1. Forced type conversion

In Golang, you can use forced type conversion to convert floating point numbers into integers. For example:

f := 3.14
i := int(f)

In this example, we convert the floating point number 3.14 to an integer and get the integer value 3. It should be noted that cast type conversion will discard the decimal part and only retain the integer part. If we cast a negative number, the decimal part will be rounded towards zero. For example:

f := -3.14
i := int(f)

In this example, the value of i is -3, not -4. This is because the cast rounds the fractional part toward zero instead of rounding off.

2. math package function

The math package in Golang provides some functions for converting floating point numbers to integers, such as Round, Ceil and Floor. These functions can round, round up, or round down as needed. For example:

f := 3.14
i := int(math.Round(f))
j := int(math.Ceil(f))
k := int(math.Floor(f))

In this example, we use the Round function to round the floating point number 3.14 to the nearest integer, getting the integer value 3; use the Ceil function to round the floating point number 3.14 up, getting the integer value 4; Use the Floor function to round down the floating point number 3.14 to get the integer value 3.

It should be noted that these functions all return float64 type values, which need to be converted to integers using cast.

3. strconv package functions

The strconv package in Golang provides some functions for converting between string and numeric types. Among them, the Atoi and ParseInt functions can convert string type numbers to integer types. For example:

s := "123"
i, _ := strconv.Atoi(s)
j, _ := strconv.ParseInt(s, 10, 0)

In this example, we use the Atoi function to convert the string "123" to an integer type, and get the integer value 123; we can also use the ParseInt function to convert the string "123" to an integer type, The radix parameter is 10, which means decimal, and the bitSize parameter, which is 0, means the integer type is automatically determined. It should be noted that the ParseInt function can also convert strings to integers in other bases, such as hexadecimal, octal, etc.

4. Decimal number control

When converting floating point numbers to integers, you need to pay attention to accuracy issues. Because floating-point numbers are approximate when stored in a computer, there may be precision errors. If the error when converting a floating point number to an integer exceeds the number of digits in the integer part, the result may be inaccurate. For example:

f := 1.0000000009
i := int(f)

In this example, the floating point number 1.0000000009 is represented as 1.0000000009000001 in Golang, and when converted to an integer, the integer value 1 is obtained, not 2. This is because the precision error exceeds the number of digits in the integer part.

To avoid this situation, the precision error can be reduced by controlling the number of decimal points. For example:

f := 1.0000000009
f = math.Round(f*1000000000) / 1000000000
i := int(f)

In this example, we control the number of decimal points within 9 digits, and use the following math.Round function to round the floating point number 1.0000000009 to the nearest decimal place to obtain the floating point value 1.000000001. And convert it to integer type, getting integer value 1. In this way, it is possible to avoid accuracy errors exceeding the number of digits in the integer part while maintaining high accuracy.

Summary

When converting Golang floating point numbers to integers, you can use forced type conversion, math package function, strconv package function, etc. You need to pay attention to precision issues, control the number of decimal points to reduce errors, and choose appropriate methods and functions to improve code readability and performance.

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