在JavaScript中替换字符串/字符的所有实例的最快方法是什么?while, for循环,正则表达式?


当前回答

@Gumbo添加额外的答案- user.email.replace(/foo/gi,"bar");

/foo/g - Refers to the all string to replace matching the case sensitive

/foo/gi - Refers to the without case sensitive and replace all For Eg: (Foo, foo, FoO, fOO)

DEMO

其他回答

最简单的方法是使用带有g标志的正则表达式来替换所有实例:

str.replace(/foo/g, "bar")

这将把字符串str中出现的所有foo替换为bar。如果你只有一个字符串,你可以像这样将它转换为RegExp对象:

var pattern = "foobar",
    re = new RegExp(pattern, "g");

使用String对象的replace()方法。

正如所选答案中提到的,应该在正则表达式中使用/g标志,以便替换字符串中子字符串的所有实例。

我认为真正的答案是,这完全取决于你的输入是什么样的。我创建了一个JsFiddle来尝试这些方法,并针对各种输入创建了自己的JsFiddle。无论我如何看待这些结果,我都看不到明显的赢家。

RegExp wasn't the fastest in any of the test cases, but it wasn't bad either. Split/Join approach seems fastest for sparse replacements. This one I wrote seems fastest for small inputs and dense replacements: function replaceAllOneCharAtATime(inSource, inToReplace, inReplaceWith) { var output=""; var firstReplaceCompareCharacter = inToReplace.charAt(0); var sourceLength = inSource.length; var replaceLengthMinusOne = inToReplace.length - 1; for(var i = 0; i < sourceLength; i++){ var currentCharacter = inSource.charAt(i); var compareIndex = i; var replaceIndex = 0; var sourceCompareCharacter = currentCharacter; var replaceCompareCharacter = firstReplaceCompareCharacter; while(true){ if(sourceCompareCharacter != replaceCompareCharacter){ output += currentCharacter; break; } if(replaceIndex >= replaceLengthMinusOne) { i+=replaceLengthMinusOne; output += inReplaceWith; //was a match break; } compareIndex++; replaceIndex++; if(i >= sourceLength){ // not a match break; } sourceCompareCharacter = inSource.charAt(compareIndex) replaceCompareCharacter = inToReplace.charAt(replaceIndex); } replaceCompareCharacter += currentCharacter; } return output; }

var mystring = 'This is a string';
var newString = mystring.replace(/i/g, "a");

newString现在是'Thas as a strange '

像这样使用正则表达式对象

var regex = new RegExp(' ' ', 'g'); STR = STR .replace(regex, '\ ");

它将取代所有出现的“into”。