[Golang] To use regex to filter and give any values you want.

Ví dụ như bạn có 1 ký tự 52.2 m² và bạn muốn lấy 52.2 sau đó lưu vào database.

Certainly! Let’s break down the regular expression and the code:

The Regular Expression: (\d+(\.\d+)?)\s*m?

1. (\d+(\.\d+)?)

• This is the main capturing group that captures the area value.
• \d+: Matches one or more digits (0-9). This will match whole numbers.
• (\.\d+)?: This is a nested capturing group that matches a decimal point followed by one or more digits. The ? at the end makes this whole group optional, so the regex can match both whole numbers and decimal numbers.
  • \.: Matches a literal decimal point.
  • \d+: Matches one or more digits after the decimal point.

1. \s*

• Matches zero or more whitespace characters. This allows for potential spaces between the number and the “m”.

1. m?

• Matches the letter ‘m’ zero or one time. The ? makes it optional. This can be useful if sometimes the input might just say “52.2m” instead of “52.2 m²”.

The Code:

1. areaRegex := regexp.MustCompile((\d+(.\d+)?)\s*m?)

• This line compiles the regular expression. MustCompile will panic if the regex does not compile correctly, ensuring that invalid patterns are caught during program initialization.

1. areaMatch := areaRegex.FindStringSubmatch(str)

• FindStringSubmatch searches for the pattern in the provided string and returns the matches in a slice. The first item in the slice (areaMatch[0]) is the entire matched string, and the subsequent items are the captured groups. In our case, areaMatch[1] will contain the area value we’re interested in.

1. if len(areaMatch) > 0 { ... }

• Checks if there was a match. If there was a match, the length of areaMatch will be greater than 0.

1. fmt.Println("Area:", areaMatch[1])

• Prints the captured area value.

So, when the string “52.2 m²” is processed with this code, the regular expression will recognize “52.2” as the area value and print it out.