刚才在听音乐看Coursera公开课视频的时候，突然发现了音量键的作用。

人的耳朵在聆听一首音乐曲子的时候，会有美妙的感受。如果现在有两首曲子，都是很好听的，但是把它们一同播放，则听的人会感觉到很杂乱，享受不到这两首曲子单独播放时带来的喜悦和感动。

然而，我发现，有时候边听音乐边看书，效率还是挺高的，而且心情很愉快。这时候，美妙的乐曲就像是背景音乐一样，它并不会影响我正常阅读时注意力的集中。相反，音乐还有可能帮助我记忆一些东西。我一直觉得音乐是神奇的，同一段音乐，我可能听过好几次，可是当再次听到的时候，我往往脑中会立刻浮现前几次听到这段音乐时的场景，包括在什么地方、当时在做什么事情，都一一浮现出来，很清晰。这就是音乐神奇的记忆力量。

清晨五点半，起床，骑着自行车出发。

今天梦梦要去济南开会，我去本部送送她。

清晨，有好多路走不通。有的路口保安还没起来上班，门是关着的，于是我只好绕路。

清晨，我走了平时不会走的路线，骑车骑上了平时不愿骑的陡坡。新路线有障碍，陡坡花力气，但是一旦越过，发现自己原来是很有力量的。清晨让我觉得充满希望与活力。

Introduction

For this first programming assignment you will write three functions that are meant to interact with dataset that accompanies this assignment. The dataset is contained in a zip file specdata.zip that you can download from the Coursera web site.

Data

The zip file containing the data can be downloaded here:

• specdata.zip [2.4MB]

The zip file contains 332 comma-separated-value (CSV) files containing pollution monitoring data for fine particulate matter (PM) air pollution at 332 locations in the United States. Each file contains data from a single monitor and the ID number for each monitor is contained in the file name. For example, data for monitor 200 is contained in the file “200.csv”. Each file contains three variables:

• Date: the date of the observation in YYYY-MM-DD format (year-month-day)

• sulfate: the level of sulfate PM in the air on that date (measured in micrograms per cubic meter)

• nitrate: the level of nitrate PM in the air on that date (measured in micrograms per cubic meter)

For this programming assignment you will need to unzip this file and create the directory ‘specdata’. Once you have unzipped the zip file, do not make any modifications to the files in the ‘specdata’ directory. In each file you’ll notice that there are many days where either sulfate or nitrate (or both) are missing (coded as NA). This is common with air pollution monitoring data in the United States.

今天看到一个很好的tutorial，学习了之后，精简地写出了以下的两个function。前一个是从基本思想出发来写，后一个是对前一个的优化版本。后者在处理数量很大的CSV文件操作时会显出优势。

演讲链接：http://v.163.com/movie/2014/5/T/Q/M9TCRI0FA_M9TCSMKTQ.html

部分精彩观点截取：

Harvard remains what it was when I first arrived on campus 50 years ago. Its purpose is not only to advance knowledge, but to advance the ideals of our nation. Great universities are places where people of all backgrounds, holding all beliefs, pursuing all questions can come to study and debate their ideas freely and openly. Today, I’d like to talk with you about how important it is for that freedom to exist for everyone, no matter how strongly we may disagree with another’s viewpoint. Tolerance for other people’s ideas and the freedom to express your own are inseparable values at great universities. Joined together, they form a sacred trust that holds the basis of our democratic society.

今天是罗老师的生日，我和梦梦在食堂打了几个菜，去他家和他一起吃午饭。

罗老师是梦梦的催眠课老师，是个平静、简单的老人。他家里的家具都很陈旧了，木质桌椅间散发着淡淡的岁月流转的味道。

我们吃过午饭，罗老师拿起他身旁的木吉他，边弹边唱起来。他喜欢听邓丽君的歌，好多歌他都熟悉调性并记得歌词。他想到什么歌，就让我用手机搜一下放出来，他跟着弹唱。每一曲结束时，他都想好下一首想唱的歌，我就一首一首地听他唱。

今晚和梦梦一起看了《伴我同行》，哆啦A梦真是可爱。

今晚看了《阿甘正传》，不知道要写什么感想，只是看完发现右眼有些眼泪。

MBTI简介

闲来无事，做了下MBTI测试——国际最为流行的职业人格评估测试。

20世纪40年代，美国一对母女在荣格的心理学类型理论的基础上提出了一套个性测验模型。伊莎贝尔·迈尔斯（Isabel Myers）和凯瑟琳·布里格斯（Katharine Briggs）把这套理论模型以她们的名字命名，叫作Myers-Briggs类型指标MBTI（Myers-Briggs Type Indicator）。