为什么运行下面显示的代码会出错？ （它在Coursera的斯坦福'启动工程'课程中的一个作业中使用：https://class.coursera.org/startup-001/quiz/attempt?quiz_id=149）
这个课程是在2013年6月 - 6月进行的，所以可能有节点或csv的更新破坏了脚本吗？作业不是关于修复脚本，所以这个问题不是“作弊”，而且课程目前还没有运行..
所以，环境是： Ubuntu 14.04（内核3-13-0-29-通用）， 节点v0.11.13， npm v1.4.9
我在主目录中有npm install'd csv，accounting util和restler，脚本也在那里。
这让我完全难过......： - （
错误消息：
[ubuntu@ip-xxx-xxx-xxx-xxx:~]$node market-research.js
Invoked at command line.
Wrote market-research.csv
Symbol Name Market Cap Previous Close Price P/E Ratio Shares EPS Earnings
/home/ubuntu/market-research.js:47
csv()
^
TypeError: object is not a function
at csv2console (/home/ubuntu/market-research.js:47:5)
at Request.response2console (/home/ubuntu/market-research.js:65:13)
at Request.EventEmitter.emit (events.js:110:17)
at Request.mixin._fireSuccess (/home/ubuntu/node_modules/restler/lib/restler.js:226:10)
at /home/ubuntu/node_modules/restler/lib/restler.js:158:20
at IncomingMessage.parsers.auto (/home/ubuntu/node_modules/restler/lib/restler.js:394:7)
at Request.mixin._encode (/home/ubuntu/node_modules/restler/lib/restler.js:195:29)
at /home/ubuntu/node_modules/restler/lib/restler.js:154:16
at Request.mixin._decode (/home/ubuntu/node_modules/restler/lib/restler.js:170:7)
at IncomingMessage.<anonymous> (/home/ubuntu/node_modules/restler/lib/restler.js:147:14)
[ubuntu@ip-xxx-xxx-xxx-xxx:~]$
代码：
#!/usr/bin/env node
/*
Use the Yahoo Finance CSV API to do some basic market research calculations.
- Background: http://greenido.wordpress.com/2009/12/22/yahoo-finance-hidden-api/
- Example URL: http://finance.yahoo.com/d/quotes.csv?s=GOOG+FB+AAPL&f=snj1pr
s: Symbol
n: Name
j1: Market Capitalization (in billions)
p: Price-per-share (at previous close)
r: Price to Earnings Ratio
Further references.
- https://github.com/danwrong/restler
- https://github.com/wdavidw/node-csv
- http://josscrowcroft.github.io/accounting.js
- http://stackoverflow.com/questions/4981891/node-js-equivalent-of-pythons-if-name-main
- http://nodejs.org/docs/latest/api/util.html#util_util_format_format
*/
var util = require('util');
var fs = require('fs');
var rest = require('restler');
var csv = require('csv');
var accounting = require('accounting');
var CSVFILE_DEFAULT = "market-research.csv";
var SYMBOLS_DEFAULT = ["GOOG", "FB", "AAPL", "YHOO", "MSFT", "LNKD", "CRM"];
var COLUMNS_DEFAULT = 'snj1pr'; // http://greenido.wordpress.com/2009/12/22/yahoo-finance-hidden-api
var HEADERS_DEFAULT = ["Symbol", "Name", "Market Cap", "Previous Close Price",
"P/E Ratio", "Shares", "EPS", "Earnings"];
var financeurl = function(symbols, columns) {
return util.format(
'http://finance.yahoo.com/d/quotes.csv?s=%s&f=%s',
symbols.join('+'),
columns);
};
var marketCapFloat = function(marketCapString) {
return parseFloat(marketCapString.split('B')[0]) * 1e9;
};
var csv2console = function(csvfile, headers) {
console.log(headers.join("\t"));
csv()
.from.path(csvfile)
.on('record', function(row, index) {
var shares = Math.round(marketCapFloat(row[2])/row[3], 0);
var eps = (row[3]/row[4]).toFixed(3);
var earnings = accounting.formatMoney(eps * shares);
outrow = row.concat([shares, eps, earnings]);
console.log(outrow.join("\t"));
});
};
var buildfn = function(csvfile, headers) {
var response2console = function(result, response) {
if (result instanceof Error) {
console.error('Error: ' + util.format(response.message));
} else {
console.error("Wrote %s", csvfile);
fs.writeFileSync(csvfile, result);
csv2console(csvfile, headers);
}
};
return response2console;
};
var marketResearch = function(symbols, columns, csvfile, headers) {
symbols = symbols || SYMBOLS_DEFAULT;
columns = columns || COLUMNS_DEFAULT;
csvfile = csvfile || CSVFILE_DEFAULT;
headers = headers || HEADERS_DEFAULT;
var apiurl = financeurl(symbols, columns);
var response2console = buildfn(csvfile, headers);
rest.get(apiurl).on('complete', response2console);
};
if(require.main == module) {
console.error('Invoked at command line.');
var symbols = process.argv;
if(symbols.length > 2) {
symbols = symbols.slice(2, symbols.length);
} else {
symbols = undefined;
};
marketResearch(symbols);
} else {
console.error('Invoked via library call');
}
exports.marketResearch = marketResearch;
脚本创建的market-research.csv的内容：
"GOOG","Google Inc.",386.6B,569.20,29.49
"FB","Facebook, Inc.",194.5B,73.855,78.49
"AAPL","Apple Inc.",613.8B,102.25,16.49
"YHOO","Yahoo! Inc.",38.302B,38.31,33.11
"MSFT","Microsoft Corpora",374.3B,44.88,17.06
"LNKD","LinkedIn Corporat",27.747B,223.26,N/A
"CRM","Salesforce.com In",36.577B,58.29,N/A
答案 0 :(得分：7)
Quantas 94 Heavy，感谢提示。
12个月前，node-csv版本为0.2，但现在为0.4，API已经改变。
我现在编写了csv-console功能，如下所示：
// part of file market-script.js
// edited by Jeff Moye (Moyesoft)
// no attribution in the original file
var csv2console = function(csvfile, headers) {
console.log(headers.join("\t"));
var parser = csv.parse(); //create the parser
parser.on('readable', function(){ //the 'record' event no longer exists
// so instead we write a handler for the
// 'readable' event
while(record = parser.read()){ // and read() each record in a loop
var shares = Math.round(marketCapFloat(record[2])/record[3], 0);
var eps = (record[3]/record[4]).toFixed(3);
var earnings = accounting.formatMoney(eps * shares);
outrow = record.concat([shares, eps, earnings]);
console.log(outrow.join("\t"));
}
});
parser.on('error', function(err){ // we may as well have an error handler
console.log(err.message);
});
fs.createReadStream(csvfile).pipe(parser); //open file as a stream and pipe it to the parser
};