如何解析CSV数据? - 开卷题库

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最佳答案

你可以使用本博客中提到的CSVToArray ()函数。

<script type="text/javascript">
// ref: http://stackoverflow.com/a/1293163/2343
// 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 ){
// 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( [] );


}


var strMatchedValue;


// 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.
strMatchedValue = arrMatches[ 2 ].replace(
new RegExp( "\"\"", "g" ),
"\""
);


} else {


// We found a non-quoted value.
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 );
}


</script>

小开

我不知道为什么我不能得到Kirtan的例子为我工作。它似乎在空字段或带尾随逗号的字段上失败了……

这个似乎可以同时处理这两个问题。

我没有编写解析器代码，只是对解析器函数进行了包装，以使其适用于文件。看到归因。

    var Strings = {
/**
* Wrapped CSV line parser
* @param s      String delimited CSV string
* @param sep    Separator override
* @attribution: http://www.greywyvern.com/?post=258 (comments closed on blog :( )
*/
parseCSV : function(s,sep) {
// http://stackoverflow.com/questions/1155678/javascript-string-newline-character
var universalNewline = /\r\n|\r|\n/g;
var a = s.split(universalNewline);
for(var i in a){
for (var f = a[i].split(sep = sep || ","), x = f.length - 1, tl; x >= 0; x--) {
if (f[x].replace(/"\s+$/, '"').charAt(f[x].length - 1) == '"') {
if ((tl = f[x].replace(/^\s+"/, '"')).length > 1 && tl.charAt(0) == '"') {
f[x] = f[x].replace(/^\s*"|"\s*$/g, '').replace(/""/g, '"');
} else if (x) {
f.splice(x - 1, 2, [f[x - 1], f[x]].join(sep));
} else f = f.shift().split(sep).concat(f);
} else f[x].replace(/""/g, '"');
} a[i] = f;
}
return a;
}
}

小开

jQuery-CSV

它是一个jQuery插件，设计用于将CSV解析为JavaScript数据的端到端解决方案。它处理RFC 4180中呈现的每一个边缘情况，以及一些为Excel/谷歌电子表格导出弹出的情况(即，主要涉及空值)，这些都是规范所缺少的。

例子:

轨道,艺术家,专辑,

危险，“巴斯塔韵脚”，“当灾难袭来”，1997年

// Calling this
music = $.csv.toArrays(csv)


// Outputs...
[
["track", "artist", "album", "year"],
["Dangerous", "Busta Rhymes", "When Disaster Strikes", "1997"]
]


console.log(music[1][2]) // Outputs: 'When Disaster Strikes'

更新:

哦，是的，我还应该提一下，它是完全可配置的。

music = $.csv.toArrays(csv, {
delimiter: "'", // Sets a custom value delimiter character
separator: ';', // Sets a custom field separator character
});

更新2:

它现在也可以在Node.js上使用jQuery。因此，您可以选择使用相同的库进行客户端或服务器端解析。

更新3:

自从谷歌代码关闭后，jquery-csv已经迁移到GitHub。

免责声明:我也是jQuery-CSV的作者。

小开

下面是我的PEG(.js)语法，在RFC 4180中似乎做得不错(即它处理http://en.wikipedia.org/wiki/Comma-separated_values的例子):

start
= [\n\r]* first:line rest:([\n\r]+ data:line { return data; })* [\n\r]* { rest.unshift(first); return rest; }


line
= first:field rest:("," text:field { return text; })*
& { return !!first || rest.length; } // ignore blank lines
{ rest.unshift(first); return rest; }


field
= '"' text:char* '"' { return text.join(''); }
/ text:[^\n\r,]* { return text.join(''); }


char
= '"' '"' { return '"'; }
/ [^"]

在http://jsfiddle.net/knvzk/10或http://pegjs.majda.cz/online试试。在https://gist.github.com/3362830下载生成的解析器。

小开

只需使用.split(','):

var str = "How are you doing today?";
var n = str.split(" ");

小开

我有一个实现作为电子表格项目的一部分。

此代码尚未经过全面测试，但欢迎任何人使用它。

正如一些答案所指出的那样，如果你实际上有深潜器或TSV文件，你的实现可以简单得多，因为它们不允许在值中使用记录和字段分隔符。另一方面，CSV实际上可以在字段中使用逗号和换行符，这打破了大多数正则表达式和基于分割的方法。

var CSV = {
parse: function(csv, reviver) {
reviver = reviver || function(r, c, v) { return v; };
var chars = csv.split(''), c = 0, cc = chars.length, start, end, table = [], row;
while (c < cc) {
table.push(row = []);
while (c < cc && '\r' !== chars[c] && '\n' !== chars[c]) {
start = end = c;
if ('"' === chars[c]){
start = end = ++c;
while (c < cc) {
if ('"' === chars[c]) {
if ('"' !== chars[c+1]) {
break;
}
else {
chars[++c] = ''; // unescape ""
}
}
end = ++c;
}
if ('"' === chars[c]) {
++c;
}
while (c < cc && '\r' !== chars[c] && '\n' !== chars[c] && ',' !== chars[c]) {
++c;
}
} else {
while (c < cc && '\r' !== chars[c] && '\n' !== chars[c] && ',' !== chars[c]) {
end = ++c;
}
}
row.push(reviver(table.length-1, row.length, chars.slice(start, end).join('')));
if (',' === chars[c]) {
++c;
}
}
if ('\r' === chars[c]) {
++c;
}
if ('\n' === chars[c]) {
++c;
}
}
return table;
},


stringify: function(table, replacer) {
replacer = replacer || function(r, c, v) { return v; };
var csv = '', c, cc, r, rr = table.length, cell;
for (r = 0; r < rr; ++r) {
if (r) {
csv += '\r\n';
}
for (c = 0, cc = table[r].length; c < cc; ++c) {
if (c) {
csv += ',';
}
cell = replacer(r, c, table[r][c]);
if (/[,\r\n"]/.test(cell)) {
cell = '"' + cell.replace(/"/g, '""') + '"';
}
csv += (cell || 0 === cell) ? cell : '';
}
}
return csv;
}
};

小开

下面是一个极其简单的CSV解析器，它处理带有逗号、新行和转义双引号的引号字段。没有分裂或正则表达式。它每次扫描输入字符串1-2个字符，并构建一个数组。

在http://jsfiddle.net/vHKYH/测试它。

function parseCSV(str) {
var arr = [];
var quote = false;  // 'true' means we're inside a quoted field


// Iterate over each character, keep track of current row and column (of the returned array)
for (var row = 0, col = 0, c = 0; c < str.length; c++) {
var cc = str[c], nc = str[c+1];        // Current character, next character
arr[row] = arr[row] || [];             // Create a new row if necessary
arr[row][col] = arr[row][col] || '';   // Create a new column (start with empty string) if necessary


// If the current character is a quotation mark, and we're inside a
// quoted field, and the next character is also a quotation mark,
// add a quotation mark to the current column and skip the next character
if (cc == '"' && quote && nc == '"') { arr[row][col] += cc; ++c; continue; }


// If it's just one quotation mark, begin/end quoted field
if (cc == '"') { quote = !quote; continue; }


// If it's a comma and we're not in a quoted field, move on to the next column
if (cc == ',' && !quote) { ++col; continue; }


// If it's a newline (CRLF) and we're not in a quoted field, skip the next character
// and move on to the next row and move to column 0 of that new row
if (cc == '\r' && nc == '\n' && !quote) { ++row; col = 0; ++c; continue; }


// If it's a newline (LF or CR) and we're not in a quoted field,
// move on to the next row and move to column 0 of that new row
if (cc == '\n' && !quote) { ++row; col = 0; continue; }
if (cc == '\r' && !quote) { ++row; col = 0; continue; }


// Otherwise, append the current character to the current column
arr[row][col] += cc;
}
return arr;
}

小开

csvToArray v1.3

一个紧凑(645字节)，但兼容的函数，将CSV字符串转换为2D数组，符合RFC4180标准。

https://code.google.com/archive/p/csv-to-array/downloads

常用用法:jQuery

 $.ajax({
url: "test.csv",
dataType: 'text',
cache: false
}).done(function(csvAsString){
csvAsArray=csvAsString.csvToArray();
});

常用用法:JavaScript

csvAsArray = csvAsString.csvToArray();

覆盖字段分隔符

csvAsArray = csvAsString.csvToArray("|");

覆盖记录分离器

csvAsArray = csvAsString.csvToArray("", "#");

覆盖跳过报头

csvAsArray = csvAsString.csvToArray("", "", 1);

覆盖所有

csvAsArray = csvAsString.csvToArray("|", "#", 1);

小开

正则表达式拯救你!这几行代码根据RFC 4180标准处理带有嵌入逗号、引号和换行符的正确引用字段。

function parseCsv(data, fieldSep, newLine) {
fieldSep = fieldSep || ',';
newLine = newLine || '\n';
var nSep = '\x1D';
var qSep = '\x1E';
var cSep = '\x1F';
var nSepRe = new RegExp(nSep, 'g');
var qSepRe = new RegExp(qSep, 'g');
var cSepRe = new RegExp(cSep, 'g');
var fieldRe = new RegExp('(?<=(^|[' + fieldSep + '\\n]))"(|[\\s\\S]+?(?<![^"]"))"(?=($|[' + fieldSep + '\\n]))', 'g');
var grid = [];
data.replace(/\r/g, '').replace(/\n+$/, '').replace(fieldRe, function(match, p1, p2) {
return p2.replace(/\n/g, nSep).replace(/""/g, qSep).replace(/,/g, cSep);
}).split(/\n/).forEach(function(line) {
var row = line.split(fieldSep).map(function(cell) {
return cell.replace(nSepRe, newLine).replace(qSepRe, '"').replace(cSepRe, ',');
});
grid.push(row);
});
return grid;
}


const csv = 'A1,B1,C1\n"A ""2""","B, 2","C\n2"';
const separator = ',';      // field separator, default: ','
const newline = ' <br /> '; // newline representation in case a field contains newlines, default: '\n'
var grid = parseCsv(csv, separator, newline);
// expected: [ [ 'A1', 'B1', 'C1' ], [ 'A "2"', 'B, 2', 'C <br /> 2' ] ]

您不需要像lex/yacc这样的解析器-生成器。正则表达式可以正确地处理RFC 4180，这要归功于正向向后查找、反向向后查找和正向向前查找。

克隆/下载代码在https://github.com/peterthoeny/parse-csv-js

小开

我已经构造了这个JavaScript脚本来解析字符串到数组对象中的CSV。我发现最好将整个CSV分解成行、字段并相应地处理它们。我认为这将使您更容易更改代码以满足您的需要。

    //
//
// CSV to object
//
//


const new_line_char = '\n';
const field_separator_char = ',';


function parse_csv(csv_str) {


var result = [];


let line_end_index_moved = false;
let line_start_index = 0;
let line_end_index = 0;
let csr_index = 0;
let cursor_val = csv_str[csr_index];
let found_new_line_char = get_new_line_char(csv_str);
let in_quote = false;


// Handle \r\n
if (found_new_line_char == '\r\n') {
csv_str = csv_str.split(found_new_line_char).join(new_line_char);
}
// Handle the last character is not \n
if (csv_str[csv_str.length - 1] !== new_line_char) {
csv_str += new_line_char;
}


while (csr_index < csv_str.length) {
if (cursor_val === '"') {
in_quote = !in_quote;
} else if (cursor_val === new_line_char) {
if (in_quote === false) {
if (line_end_index_moved && (line_start_index <= line_end_index)) {
result.push(parse_csv_line(csv_str.substring(line_start_index, line_end_index)));
line_start_index = csr_index + 1;
} // Else: just ignore line_end_index has not moved or line has not been sliced for parsing the line
} // Else: just ignore because we are in a quote
}
csr_index++;
cursor_val = csv_str[csr_index];
line_end_index = csr_index;
line_end_index_moved = true;
}


// Handle \r\n
if (found_new_line_char == '\r\n') {
let new_result = [];
let curr_row;
for (var i = 0; i < result.length; i++) {
curr_row = [];
for (var j = 0; j < result[i].length; j++) {
curr_row.push(result[i][j].split(new_line_char).join('\r\n'));
}
new_result.push(curr_row);
}
result = new_result;
}
return result;
}


function parse_csv_line(csv_line_str) {


var result = [];


//let field_end_index_moved = false;
let field_start_index = 0;
let field_end_index = 0;
let csr_index = 0;
let cursor_val = csv_line_str[csr_index];
let in_quote = false;


// Pretend that the last char is the separator_char to complete the loop
csv_line_str += field_separator_char;


while (csr_index < csv_line_str.length) {
if (cursor_val === '"') {
in_quote = !in_quote;
} else if (cursor_val === field_separator_char) {
if (in_quote === false) {
if (field_start_index <= field_end_index) {
result.push(parse_csv_field(csv_line_str.substring(field_start_index, field_end_index)));
field_start_index = csr_index + 1;
} // Else: just ignore field_end_index has not moved or field has not been sliced for parsing the field
} // Else: just ignore because we are in quote
}
csr_index++;
cursor_val = csv_line_str[csr_index];
field_end_index = csr_index;
field_end_index_moved = true;
}
return result;
}


function parse_csv_field(csv_field_str) {
with_quote = (csv_field_str[0] === '"');


if (with_quote) {
csv_field_str = csv_field_str.substring(1, csv_field_str.length - 1); // remove the start and end quotes
csv_field_str = csv_field_str.split('""').join('"'); // handle double quotes
}
return csv_field_str;
}


// Initial method: check the first newline character only
function get_new_line_char(csv_str) {
if (csv_str.indexOf('\r\n') > -1) {
return '\r\n';
} else {
return '\n'
}
}

小开

下面是我简单的JavaScript代码:

let a = 'one,two,"three, but with a comma",four,"five, with ""quotes"" in it.."'
console.log(splitQuotes(a))


function splitQuotes(line) {
if(line.indexOf('"') < 0)
return line.split(',')


let result = [], cell = '', quote = false;
for(let i = 0; i < line.length; i++) {
char = line[i]
if(char == '"' && line[i+1] == '"') {
cell += char
i++
} else if(char == '"') {
quote = !quote;
} else if(!quote && char == ',') {
result.push(cell)
cell = ''
} else {
cell += char
}
if ( i == line.length-1 && cell) {
result.push(cell)
}
}
return result
}

小开

这是另一个解决方案。这个用途:

一个粗略的全局正则表达式，用于分割CSV字符串(包括引号和逗号)
用于清除周围引号和尾随逗号的细粒度正则表达式
此外，还具有区分字符串、数字、布尔值和空值的类型更正

对于以下输入字符串:

"This is\, a value",Hello,4,-123,3.1415,'This is also\, possible',true,

代码输出:

[
"This is, a value",
"Hello",
4,
-123,
3.1415,
"This is also, possible",
true,
null
]

下面是我在一个可运行的代码片段中实现的parseCSVLine():

function parseCSVLine(text) {
return text.match( /\s*(\"[^"]*\"|'[^']*'|[^,]*)\s*(,|$)/g ).map( function (text) {
let m;
if (m = text.match(/^\s*,?$/)) return null; // null value
if (m = text.match(/^\s*\"([^"]*)\"\s*,?$/)) return m[1]; // Double Quoted Text
if (m = text.match(/^\s*'([^']*)'\s*,?$/)) return m[1]; // Single Quoted Text
if (m = text.match(/^\s*(true|false)\s*,?$/)) return m[1] === "true"; // Boolean
if (m = text.match(/^\s*((?:\+|\-)?\d+)\s*,?$/)) return parseInt(m[1]); // Integer Number
if (m = text.match(/^\s*((?:\+|\-)?\d*\.\d*)\s*,?$/)) return parseFloat(m[1]); // Floating Number
if (m = text.match(/^\s*(.*?)\s*,?$/)) return m[1]; // Unquoted Text
return text;
} );
}


let data = `"This is\, a value",Hello,4,-123,3.1415,'This is also\, possible',true,`;
let obj = parseCSVLine(data);
console.log( JSON.stringify( obj, undefined, 2 ) );

小开

只是随便说说而已。我最近遇到了用Javascript解析CSV列的需求，我选择了自己的简单的解决方案。它满足了我的需要，也可能帮助到其他人。

const csvString = '"Some text, some text",,"",true,false,"more text","more,text, more, text ",true';


const parseCSV = text => {
const lines = text.split('\n');
const output = [];


lines.forEach(line => {
line = line.trim();


if (line.length === 0) return;


const skipIndexes = {};
const columns = line.split(',');


output.push(columns.reduce((result, item, index) => {
if (skipIndexes[index]) return result;


if (item.startsWith('"') && !item.endsWith('"')) {
while (!columns[index + 1].endsWith('"')) {
index++;
item += `,${columns[index]}`;
skipIndexes[index] = true;
}


index++;
skipIndexes[index] = true;
item += `,${columns[index]}`;
}


result.push(item);
return result;
}, []));
});


return output;
};


console.log(parseCSV(csvString));