Golang | Extracting Regular Expression from the Slice

A regular expression is a sequence of characters which define a search pattern. Go language support regular expressions. A regular expression is used for parsing, filtering, validating, and extracting meaningful information from large text, like logs, the output generated from other programs, etc.
In Go regexp, you are allowed to find a regular expression in the given string with the help of Find() method. This method returns a slice which is holding the text of the leftmost match in the original slice of the regular expression. Or return nil if no match found. This method is defined under the regexp package, so for accessing this method you need to import the regexp package in your program.

Syntax:

func (re *Regexp) Find(s []byte) []byte

Example 1:

// Go program to illustrate how to
// find regexp from the given slice
package main

import (
    "fmt"
    "regexp"
)

// Main function
func main() {

    // Finding regexp from the
    // given slice of bytes
    // Using  Find() method
    m := regexp.MustCompile(`geeks?`)

    fmt.Printf("%q\n", m.Find([]byte(`GeeksgeeksGeeks, geeks`)))
    fmt.Printf("%q\n", m.Find([]byte(`Hello! geeksForGEEKs`)))
    fmt.Printf("%q\n", m.Find([]byte(`I like Go language`)))
    fmt.Printf("%q\n", m.Find([]byte(`Hello, Welcome`)))

}

Output:

"geeks"
"geeks"
""
""

Example 2:

// Go program to illustrate how to
// find regexp from the given slice
package main

import (
    "fmt"
    "regexp"
)

// Main function
func main() {

    // Finding regexp from
    // the given slice
    // Using Find() method
    m := regexp.MustCompile(`language`)
    res := m.Find([]byte(`I like Go language this language is "+
                          "very easy to learn and understand`))

    if res == nil {

        fmt.Printf("Found: %q ", res)
    } else {
        fmt.Printf("Found: %q", res)
    }
}

Output:

Found: "language"