在JavaScript中一定数量的字符后在空格处拆分字符串 [英] Split string at space after certain number of characters in Javascript
问题描述
我正在尝试创建一个工具，该工具接受输入文本并将其按特定的#个字符分割成文本块.但是，我需要确保它不会将单词中间的文本分开.
I am attempting to create a tool that takes an input text and splits it into chunks of text at a certain # of characters. However, I need to make sure it does not split the text in the middle of a word.
在我的情况下，我将字符串分割为155个字符.
In my case, I am splitting the string after 155 characters.
我已经进行了大量的搜索以尝试找到一种解决方案，但是我担心它可能比我对Javascript的理解要复杂的多.我相信我只需要做出某种逻辑即可，如果分隔符位于单词中间，则分隔符会回退到要分隔的空间，但是我不确定如何写出这样的东西.
I've done quite a lot of searching to try and find a solution, but I fear it may be more complicated than my knowledge of Javascript allows me to figure out. I believe I just need to make some sort of logic that has the splitter backtrack to a space to split if it is in the middle of a word, but I am not sure how to write out such a thing.
这是我目前的javascript代码:
Here is my javascript code at the moment:
function splitText() {
"use strict";
var str = document.getElementById("user_input").value;
var size = 195;
var chunks = new Array(Math.ceil(str.length / size)),
nChunks = chunks.length;
var newo = 0;
for (var i = 0, o = 0; i < nChunks; ++i, o = newo) {
newo += size;
chunks[i] = str.substr(o, size);
}
var newq = 0;
for (var x = 0, q = 0; x < nChunks; ++x, q = newq) {
$("#display").append("<textarea readonly>" + chunks[x] + "</textarea><br/>");
}
}
这是我的HTML:
<body>
<content>
<h1>Text Splitter</h1>
<form>
<label>Enter a Message</label>
<input type="text" name="message" id="user_input">
</form>
<form>
<input type="button" onclick="splitText();" id="submit" value="Submit!"> <br/>
</form>
<label>Your split message: </label>
<p><span id='display'></span></p>
</content>
</body>
如果您想看一下，这是当前工作形式的代码: https://jsfiddle.net/add4s7rs/7/
Here is the code in its current working form, if you'd like to take a look: https://jsfiddle.net/add4s7rs/7/
谢谢！感谢您的协助！
推荐答案
使用regexp将字符串拆分为特定长度的块的简便方法:
A short and simple way to split a string into chunks up to a certain length using a regexp:
console.log(str.match(/.{1,154}(\s|$)/g));
一些例子:
var str = 'the quick brown fox jumps over the lazy dog';
console.log(str.match(/.{1,10}(\s|$)/g))
Array [ "the quick ", "brown fox ", "jumps over ", "the lazy ", "dog" ]
console.log(str.match(/.{1,15}(\s|$)/g))
Array [ "the quick brown ", "fox jumps over ", "the lazy dog" ]
之所以可行，是因为默认情况下，量词(在本例中为{1,154})是贪婪的，会尝试匹配尽可能多的字符.将(\s|$)放在.{1,154}之后会强制匹配终止于空白字符或字符串的结尾.因此，.{1,154}(\s|$)将最多匹配154个字符，后跟一个空白字符.然后/g修饰符使它继续匹配整个字符串.
This works because quantifiers (in this case {1,154}) are by default greedy and will attempt to match as many characters as they can. putting the (\s|$) behind the .{1,154} forces the match to terminate on a whitespace character or the end of the string. So .{1,154}(\s|$) will match up to 154 characters followed by a whitespace character. The /g modifier then makes it continue to match through the entire string.
要将其放在您的函数上下文中:
To put this in the context of your function:
function splitText() {
"use strict";
var str = document.getElementById("user_input").value;
var chunks = str.match(/.{1,154}(\s|$)/g);
chunks.forEach(function (i,x) {
$("#display").append("<textarea readonly>" + chunks[x] + "</textarea><br/>");
});
}
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