如何检查文本文件是否包含整个单词？

I am trying to check if a text file contains a certain word. However it will return true even for some letters in a string. For example:

Entered string: gdo

Computer found: kingdom

var word = strings.ToLower(string(a))

// read the whole file at once
b, err := ioutil.ReadFile("words.txt")
if err != nil {
    panic(err)
}
s := string(b)

// Check whether s contains substring text
if strings.Contains(s, word) == true {
    fmt.Println("this is a word ", word)
} else {
    fmt.Println("this isn't a word ", word)
}

strings.Contains() reports if a substrings is contained within a string. It doesn't check for word boundaries, so the behaviour you're seeing is expected.

What you want instead is to recognize every word as a word. There is already the strings.Fields() function to split text by whitespace. A simple implementation might look like:

func main() {
    source := `
hello
world
kingdom
foo
`
    check := "gdo"
    words := strings.Fields(strings.ToLower(source))

    for _, w := range words {
        if w == check {
            fmt.Println("found", check)
            break
        }
    }
}

I used strings.Fields() because I don't know the contents of your words.txt file. You can also use strings.Split() if you know the separator is always a single newline or single space.

This will be slow if you're doing a lot of lookups, since it's looping over the words array for every lookup. A faster method would be to store it in a map:

func main() {
    source := `
hello
world
kingdom
foo
`
    check := "gdo"

    words := make(map[string]struct{})
    for _, w := range strings.Fields(strings.ToLower(source)) {
        words[w] = struct{}{}
    }

    _, ok := words[check]
    if ok {
        fmt.Println("found", check)
    }
}

If you're doing just a single lookup the first method will be faster (as this map method will always need to loop the full array at least once to build the map).

I used the somewhat strange looking empty struct for the map value as this doesn't allocate any memory (words[w] = true would).

Here is a simple solution. You can convert s into a string array. Then loop through the array to check if it contains the word.

var word = strings.ToLower(string(a))

// read the whole file at once
b, err := ioutil.ReadFile("words.txt")
if err != nil {
    panic(err)
}
s := string(b)

// convert the string into a string array (words)

content := strings.Split(s, " ")

contains := false

for i:=0 ; i<len(content) ; i++ {
    if content[i] == word {
        contains = true
        break
    }
}

// Check whether s contains substring text
if contains {
    fmt.Println("this is a word ", word)
} else {
    fmt.Println("this isn't a word ", word)
}

No need to complicate things. Have a great day :)