Java

牛顿法求平方根

今天要解决的是如何用牛顿法求一个数的平方根：

来看看我们的代码实现：

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package com.github.xiongdi.study;

public class Calc {
    // 设定一个误差值
    private double err = 0.001;

    public Double sqrt(int a) {
        // 设定一个初始的值
        double x = a / 2;

        // 循环的结束条件是误差小于误差值
        while (Math.abs(x * x - a) > err) {
            // 牛顿迭代式
            x = (x + a / x) / 2;
        }
        return x;
    }
}
Python

Python发送邮件

使用Python发送邮件

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#!/usr/bin/env python
# coding=UTF-8
import smtplib

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import requests

data = {
    'username': 'xiongdi',
    'password': '*****',
    'backUrl': '/csv?tag=yangsen'
}

r = requests.post('http://uservalidation.i-md.com/login', data=data)

me = 'di.xiong@i-md.com'
you = 'di.xiong@i-md.com'

# Create message container - the correct MIME type is multipart/alternative.
msg = MIMEMultipart('alternative')
msg['Subject'] = 'Link'
msg['From'] = me
msg['To'] = you

# Create the body of the message (a plain-text and an HTML version).
text = u'这是yangsen的验证用户csv文件'

# Record the MIME types of both parts - text/plain and text/html.
part1 = MIMEText(text, 'plain', 'utf-8')

part2 = MIMEText(r.text, 'plain', 'utf-8')
part2['Content-Type'] = 'application/octet-stream'
part2['Content-Disposition'] = 'attachment; filename="out.csv"'

# Attach parts into message container.
# According to RFC 2046, the last part of a multipart message, in this case
# the HTML message, is best and preferred.
msg.attach(part1)
msg.attach(part2)

# Send the message via local SMTP server.
s = smtplib.SMTP('smtp.exmail.qq.com')
# sendmail function takes 3 arguments: sender's address, recipient's address
# and message to send - here it is sent as one string.
s.login('di.xiong@i-md.com', '****')
s.sendmail(me, you, msg.as_string())
s.quit()
Node.js

使用Node做静态文件服务器

使用Node做静态文件服务器

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var http = require('http');
var send = require('send');
var url = require('url');
var request = require('request');

var app = http.createServer(function(req, res){
  // your custom error-handling logic:
  function error(err) {
    request.get('http://f.i-md.com/' + url.parse(req.url).pathname).pipe(res);
  }

  // your custom directory handling logic:
  function redirect() {
    res.statusCode = 301;
    res.setHeader('Location', req.url + '/');
    res.end('Redirecting to ' + req.url + '/');
  }

  // transfer arbitrary files from within
  // /www/example.com/public/*
  send(req, url.parse(req.url).pathname)
  .root('/tmp/cms')
  .on('error', error)
  .on('directory', redirect)
  .pipe(res);
}).listen(1338);