`indexOf` 是 JavaScript 中的一个数组方法,用于查找数组中某个元素的第一个匹配项的索引。如果元素不存在于数组中,则返回 `-1`。这个方法只能用于查找单个值,而不是多个值。 ##...
indexOf() compares searchElement to elements of the Array using strict equality (the same method used by the === or triple-equals operator). 一目了然,这里用的是严格等于(===)。大家做类似判断的时候多留意。不要误认为数字会转成字符串,同理字符串也不会转换成数字。 总结 以上就是这篇文章的全...
尝试以下示例。 JavaScript Array indexOf Methodif(!Array.prototype.indexOf){Array.prototype.indexOf=function(elt/*, from*/){varlen=this.length;varfrom=Number(arguments[1])||0;from=(from<0)?Math.ceil(from):Math.floor(from);if(from<0)from+=len;for(;from<len;from++){if(frominthis&&thi...
List.lastIndexOf method Article 26/01/2017 Dans cet article Syntax Parameters Return value Requirements See also Gets the index of the last occurrence of the specified value in a list.SyntaxJavaScript Copier var number = list.lastIndexOf(searchElement, fromIndex); ...
Using the JavaScript indexOf method on strings Let’s consider an example where we use this method to get the index of the first occurrence of the substring “flexiple.” Input: let devs = 'Join as a freelance developer at Flexiple'; let index = devs.indexOf('Flexiple'); console.log...
indexOf() compares searchElement to elements of the Array using strict equality (the same method used by the === or triple-equals operator). 一目了然,这里用的是严格等于(===)。大家做类似判断的时候多留意。不要误认为数字会转成字符串,同理字符串也不会转换成数字。
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javascript const exampleString = "Hello, this is a test string to demonstrate indexOf method."; const searchString = "test"; const index = exampleString.indexOf(searchString); console.log("The index of '" + searchString + "' is: " + index); 在这个例子中,indexOf 方法在 exampleString...
indexOf() compares searchElement to elements of the Array using strict equality (the same method used by the === or triple-equals operator). 一目了然,这里用的是严格等于(===)。大家做类似判断的时候多留意。不要误认为数字会转成字符串,同理字符串也不会转换成数字。
JavaScript String lastIndexOf() Methodvarstr1=newString("This is string one and again string");varindex=str1.lastIndexOf("string");document.write("lastIndexOf found String :"+index);document.write("");varindex=str1.lastIndexOf("one");document.write("lastIndexOf found String :"+index)...