[英]How to check if a string contain specific words?
$a = 'how are you';
if (strpos($a,'are') !== false) {
echo 'true';
}
In PHP, we can use the code above to check if a string contain specific words, but how can I do the same function in JavaScript/jQuery?在 PHP 中,我们可以使用上面的代码来检查一个字符串是否包含特定的单词,但是如何在 JavaScript/jQuery 中执行相同的功能呢?
you can use indexOf for this您可以为此使用 indexOf
var a = 'how are you';
if (a.indexOf('are') > -1) {
return true;
} else {
return false;
}
Edit : This is an old answer that keeps getting up votes every once in a while so I thought I should clarify that in the above code, the if
clause is not required at all because the expression itself is a boolean.编辑:这是一个旧的答案,每隔一段时间就会投票一次,所以我想我应该澄清一下,在上面的代码中,
if
子句根本不需要,因为表达式本身是一个布尔值。 Here is a better version of it which you should use,这是您应该使用的更好版本,
var a = 'how are you';
return a.indexOf('are') > -1;
Update in ECMAScript2016: ECMAScript2016 中的更新:
var a = 'how are you';
return a.includes('are'); //true
indexOf
/ includes
should not be used for finding whole words: indexOf
/ includes
不应用于查找整个单词: A word (in western culture) is a drawing of a symbols close to each other, with some space between each word.一个词(在西方文化中)是一个相互靠近的符号图,每个词之间有一些空间。 A word is considered as such if it's a complete piece of characters draw together and not a partial part of it:
如果一个词是一个完整的字符组合在一起而不是它的一部分,那么它就被认为是这样的:
"has a word".indexOf('wor') // 6 ("wor" is not a word in this sentence)
"has a word".includes('ha') // true ("ha" is not a word in this sentence)
Find a real whole word, not just if the letters of that word are somewhere in the string.找到一个真正的完整单词,而不仅仅是该单词的字母在字符串中的某个位置。
const wordInString = (s, word) => new RegExp('\\b' + word + '\\b', 'i').test(s); // tests [ '', // true ' ', // true 'did', // true 'id', // flase 'yo ', // flase 'you', // true 'you not' // true ].forEach(q => console.log( wordInString('dID You, or did you NOt, gEt WHy?', q) )) console.log( wordInString('did you, or did you not, get why?', 'you') // true )
var stringHasAll = (s, query) => // convert the query to array of "words" & checks EVERY item is contained in the string query.split(' ').every(q => new RegExp('\\b' + q + '\\b', 'i').test(s)); // tests [ '', // true ' ', // true 'aa', // true 'aa ', // true ' aa', // true 'd b', // false 'aaa', // false 'a b', // false 'aaaaa ', // false ].forEach(q => console.log( stringHasAll('aA bB cC dD', q) ))
If you are looking for exact words and don't want it to match things like "nightmare" (which is probably what you need), you can use a regex:如果您正在寻找确切的单词并且不希望它匹配诸如“噩梦”之类的东西(这可能是您需要的),您可以使用正则表达式:
/\bare\b/gi
\b = word boundary
g = global
i = case insensitive (if needed)
If you just want to find the characters "are", then use indexOf
.如果您只想查找字符“are”,请使用
indexOf
。
If you want to match arbitrary words, you have to programatically construct a RegExp (regular expression) object itself based on the word string and use test
.如果要匹配任意单词,则必须基于单词字符串以编程方式构造一个 RegExp(正则表达式)对象本身并使用
test
。
您正在寻找 indexOf 功能:
if (str.indexOf("are") >= 0){//Do stuff}
You might wanna use include method in JS.您可能想在 JS 中使用include方法。
var sentence = "This is my line";
console.log(sentence.includes("my"));
//returns true if substring is present.
PS: includes is case sensitive. PS:包括区分大小写。
An easy way to do it to use Regex match() method :-使用 Regex match() 方法的简单方法:-
For Example例如
var str ="Hi, Its stacks over flow and stackoverflow Rocks."
// It will check word from beginning to the end of the string
if(str.match(/(^|\W)stack($|\W)/)) {
alert('Word Match');
}else {
alert('Word not found');
}
NOTE: For adding case sensitiveness update the regex with /(^|\W)stack($|\W)/i
注意:为了添加区分大小写,请使用
/(^|\W)stack($|\W)/i
更新正则表达式
Thanks谢谢
In javascript the includes() method can be used to determines whether a string contains particular word (or characters at specified position).在 javascript 中,includes() 方法可用于确定字符串是否包含特定单词(或指定位置的字符)。 Its case sensitive.
它区分大小写。
var str = "Hello there.";
var check1 = str.includes("there"); //true
var check2 = str.includes("There"); //false, the method is case sensitive
var check3 = str.includes("her"); //true
var check4 = str.includes("o",4); //true, o is at position 4 (start at 0)
var check5 = str.includes("o",6); //false o is not at position 6
This will这将
/\bword\b/.test("Thisword is not valid");
return false
, when this one返回
false
,当这个
/\bword\b/.test("This word is valid");
will return true
.将返回
true
。
var str1 = "STACKOVERFLOW"; var str2 = "OVER"; if(str1.indexOf(str2) != -1){ console.log(str2 + " found"); }
Using a conditional ternary operator使用条件三元运算符
str = 'I am on StackOverflow';
str.match(/(^|\W)StackOverflow($|\W)/) ? 'Found. Why lie?' : 'Not Found';
If you'd like to find a single word in a string without regular expressions, you can do as follows:如果您想在没有正则表达式的字符串中查找单个单词,您可以执行以下操作:
function isWordInString(needle, haystack) {
return haystack
.split(' ')
.some(p => (p === needle));
}
isWordInString('hello', 'hello great world!'); // true
isWordInString('eat', 'hello great world!'); // false
Advantages over regex:相对于正则表达式的优势:
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