在 JavaScript 中，如何在将 csv 转换为 json 时忽略空行答案

【问题标题】：In JavaScript, how can I ignore blank lines when converting csv to json在 JavaScript 中，如何在将 csv 转换为 json 时忽略空行
【发布时间】：2016-10-20 10:57:54
【问题描述】：

我正在做一个需要我将 csv 转换为 json 的项目。我找到了一个小提琴here。唯一的问题是，如果你在末尾添加空行并转换为 json，它会将空行作为对象返回。

例如，

"Id","UserName"
"1","Sam Smith"
"2","Fred Frankly"
"1","Zachary Zupers"



...

会回来

[{"Id":"1","UserName":"Sam Smith"},
{"Id":"2","UserName":"Fred Frankly"},
{"Id":"1","UserName":"Zachary Zupers"},
{"Id":""},
{"Id":""}]

关于堆栈溢出的其他答案似乎与其他编程语言有关，虽然它们似乎回答了提问者的问题，但它们在没有解释的情况下解决了问题。如果你能解释你的答案是如何工作的，那么额外的温暖模糊。

【问题讨论】：

标签： javascript json regex csv

【解决方案1】：

添加 .trim() 以删除 strData 周围的空白区域

strData = strData.trim();

http://jsfiddle.net/AZFvQ/909/

// Source: http://www.bennadel.com/blog/1504-Ask-Ben-Parsing-CSV-Strings-With-Javascript-Exec-Regular-Expression-Command.htm
// This will parse a delimited string into an array of
// arrays. The default delimiter is the comma, but this
// can be overriden in the second argument.

function CSVToArray(strData, strDelimiter) {
    strData = strData.trim();
    // Check to see if the delimiter is defined. If not,
    // then default to comma.
    strDelimiter = (strDelimiter || ",");
    // Create a regular expression to parse the CSV values.
    var objPattern = new RegExp((
    // Delimiters.
    "(\\" + strDelimiter + "|\\r?\\n|\\r|^)" +
    // Quoted fields.
    "(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|" +
    // Standard fields.
    "([^\"\\" + strDelimiter + "\\r\\n]*))"), "gi");
    // Create an array to hold our data. Give the array
    // a default empty first row.
    var arrData = [[]];
    // Create an array to hold our individual pattern
    // matching groups.
    var arrMatches = null;
    // Keep looping over the regular expression matches
    // until we can no longer find a match.
    while (arrMatches = objPattern.exec(strData)) {
        // Get the delimiter that was found.
        var strMatchedDelimiter = arrMatches[1];
        // Check to see if the given delimiter has a length
        // (is not the start of string) and if it matches
        // field delimiter. If id does not, then we know
        // that this delimiter is a row delimiter.
        if (strMatchedDelimiter.length && (strMatchedDelimiter != strDelimiter)) {
            // Since we have reached a new row of data,
            // add an empty row to our data array.
            arrData.push([]);
        }
        // Now that we have our delimiter out of the way,
        // let's check to see which kind of value we
        // captured (quoted or unquoted).
        if (arrMatches[2]) {
            // We found a quoted value. When we capture
            // this value, unescape any double quotes.
            var strMatchedValue = arrMatches[2].replace(
            new RegExp("\"\"", "g"), "\"");
        } else {
            // We found a non-quoted value.
            var strMatchedValue = arrMatches[3];
        }
        // Now that we have our value string, let's add
        // it to the data array.
        arrData[arrData.length - 1].push(strMatchedValue);
    }
    // Return the parsed data.
    return (arrData);
}

function CSV2JSON(csv) {
    var array = CSVToArray(csv);
    var objArray = [];
    for (var i = 1; i < array.length; i++) {
        objArray[i - 1] = {};
        for (var k = 0; k < array[0].length && k < array[i].length; k++) {
            var key = array[0][k];
            objArray[i - 1][key] = array[i][k]
        }
    }

    var json = JSON.stringify(objArray);
    var str = json.replace(/},/g, "},\r\n");

    return str;
}

$("#convert").click(function() {
    var csv = $("#csv").val();
    var json = CSV2JSON(csv);
    $("#json").val(json);
});

$("#download").click(function() {
    var csv = $("#csv").val();
    var json = CSV2JSON(csv);
    window.open("data:text/json;charset=utf-8," + escape(json))
});

#heading { font-size: x-large; font-weight: bold; }
.text { width: 99%; height: 200px; }
.small { font-size: small; }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>CSV to JSON</title>
</head>
<body>
    <p id="heading">CSV to JSON Converter</p>
    <p class="small"><a href="http://jsfiddle.net/sturtevant/vUnF9/" target="_blank">JSON to CSV Converter</a>
    <hr />
    <p>Paste Your CSV Here:</p>
    <textarea id="csv" class="text">"Id","UserName"
"1","Sam Smith"
"2","Fred Frankly"
"1","Zachary Zupers"</textarea>
    <br />
    <button id="convert">Convert to JSON</button>
    &nbsp;&nbsp;
    <button id="download">Download JSON</button>
    <textarea id="json" class="text"></textarea>
    <p>Based on code posted <a href="http://www.bennadel.com/blog/1504-Ask-Ben-Parsing-CSV-Strings-With-Javascript-Exec-Regular-Expression-Command.htm" target="_blank">here on Ben Nadel's blog</a></p>
</body>
</html>

新输出

[{"Id":"1","UserName":"Sam Smith"},
{"Id":"2","UserName":"Fred Frankly"},
{"Id":"1","UserName":"Zachary Zupers"}]

【讨论】：

刚刚实现并尝试过。谢谢！我没有意识到没有更多的正则表达式会有一种简单的方法。欣赏！
这会跳过空单元格