Strings and Text Processing

Contains and Prefix

The strings package checks whether text contains or starts with another string.

text check Contains and prefix checks turn text rules into boolean values.

Contains and Prefix

domain
contains_prefix.go
Replay: real traced execution (multi-file project)
package main

import (
	"fmt"
	"strings"
)

func main() {
	var domain = "docs.egtry.dev"
	hasEgtry := strings.Contains(domain, "egtry")
	isDocs := strings.HasPrefix(domain, "docs")

	fmt.Println("domain=", domain)
	fmt.Println("hasEgtry=", hasEgtry)
	fmt.Println("isDocs=", isDocs)
}

package main

import (
	"fmt"
	"strings"
)

func main() {
	var domain = "api.egtry.dev"
	hasEgtry := strings.Contains(domain, "egtry")
	isDocs := strings.HasPrefix(domain, "docs")

	fmt.Println("domain=", domain)
	fmt.Println("hasEgtry=", hasEgtry)
	fmt.Println("isDocs=", isDocs)
}

package main

import (
	"fmt"
	"strings"
)

func main() {
	var domain = "example.com"
	hasEgtry := strings.Contains(domain, "egtry")
	isDocs := strings.HasPrefix(domain, "docs")

	fmt.Println("domain=", domain)
	fmt.Println("hasEgtry=", hasEgtry)
	fmt.Println("isDocs=", isDocs)
}

  1. domain ← "docs.egtry.dev", hasEgtry ← true, isDocs ← true

    8func main() {9  var domain→ "docs.egtry.dev" = "docs.egtry.dev" //@domain="api.egtry.dev", "example.com"10  hasEgtry→ true := strings.Contains(domain"docs.egtry.dev", "egtry")11  isDocs→ true := strings.HasPrefix(domain"docs.egtry.dev", "docs")1213  fmt.Println("domain=", domain"docs.egtry.dev")14  fmt.Println("hasEgtry=", hasEgtrytrue)15  fmt.Println("isDocs=", isDocstrue)16}
    outputdomain= docs.egtry.dev
hasEgtry= true
isDocs= true

  1. domain ← "api.egtry.dev", hasEgtry ← true, isDocs ← false

    8func main() {9  var domain→ "api.egtry.dev" = "api.egtry.dev"10  hasEgtry→ true := strings.Contains(domain"api.egtry.dev", "egtry")11  isDocs→ false := strings.HasPrefix(domain"api.egtry.dev", "docs")1213  fmt.Println("domain=", domain"api.egtry.dev")14  fmt.Println("hasEgtry=", hasEgtrytrue)15  fmt.Println("isDocs=", isDocsfalse)16}
    outputdomain= api.egtry.dev
hasEgtry= true
isDocs= false

  1. domain ← "example.com", hasEgtry ← false, isDocs ← false

    8func main() {9  var domain→ "example.com" = "example.com"10  hasEgtry→ false := strings.Contains(domain"example.com", "egtry")11  isDocs→ false := strings.HasPrefix(domain"example.com", "docs")1213  fmt.Println("domain=", domain"example.com")14  fmt.Println("hasEgtry=", hasEgtryfalse)15  fmt.Println("isDocs=", isDocsfalse)16}
    outputdomain= example.com
hasEgtry= false
isDocs= false