Look up (and Replace) values in data frame based on lookup table (with more than one column)
I’m trying to find the most elegant (simple and concise) way of replacing the value of certain columns based on matching two columns from another…
View More Look up (and Replace) values in data frame based on lookup table (with more than one column)Lookup Performance in R
Recently, I became interested in maximizing lookup performance in R. Many problems require looking up values in tables. I decided to perform some tests to…
View More Lookup Performance in RModifying data with lookup tables
In many analyses, data is read from a file, but must be modified before it can be used. For example you may want to add…
View More Modifying data with lookup tables[转]如何提高科研能力和学术水平
如何提高科研能力和学术水平作为一个研究生,对于现在的科研情况谈谈一下小感想: 1. 先看综述,后看论著 看综述搞清概念,看论著掌握方法 2. 早动手 在师兄师姐离开之前学会关键技术 3. 多数文章看摘要,少数文章看全文 掌握了一点查全文的技巧,往往会以搞到全文为乐,以至于没有时间看文章的内容,更不屑于看摘要。真正有用的全文并不多,过分追求全文是浪费,不可走极端。当然只看摘要也是不对的。 4. 集中时间看文献 看过总会遗忘。看文献的时间越分散,浪费时间越多。集中时间看更容易联系起来,形成整体印象。 5. 做好记录和标记 复印或打印的文献,直接用笔标记或批注。pdf 或html 格式的文献,可以用编辑器标亮或改变文字颜色。这是避免时间浪费的又一重要手段。否则等于没看。 6. 准备引用的文章要亲自看过。 转引造成的以讹传讹不胜枚举。 7. 注意文章的参考价值。 刊物的影响因子、文章的被引次数能反映文章的参考价值。但要注意引用这篇文章的其它文章是如何评价这篇文章的:支持还是反对,补充还是纠错。 8. 交流是最好的老师 做实验遇到困难是家常便饭。你的第一反应是什么?反复尝试?放弃?看书?这些做法都有道理,但首先应该想到的是交流。对有身份的人,私下的请教体现你对他的尊重;对同年资的人,公开的讨论可以使大家畅所欲言,而且出言谨慎。千万不能闭门造车。一个实验折腾半年,后来别人告诉你那是死路,岂不冤大头? 9. 最高层次的能力是表达能力 再好的工作最终都要靠别人认可。表达能力,体现为写和说的能力,是需要长期培养的素质。比如发现一个罕见病例,写好了发一篇论著;写不好只能发一个病例报道。比如做一个课题,写好了发一篇或数篇论著;写不好只能发一个论著摘要或被枪毙。一张图,一张表,无不是表达能力的体现。寥寥几百上千字的标书,可以赢得大笔基金;虽然关系很重要,但写得太差也不行。有人说,我不学PCR,不学spss,只要学会ppt(powerpoint)就可以了。此话有一点道理,实验室的boss 们表面上就是靠一串串ppt 行走江湖的。经常有研究生因思维敏捷条例清楚而令人肃然起敬。也经常有研究生不理解”为什么我做了大部分工作而老板却让另一个没怎么干活的人写了文章?让他去大会发言?”你没有看到人家有张口就来的本事吗? 10. 学好英语,不学二外。 如今不论去日本还是欧洲,学术交流早已是英语的天下。你不必为看不懂一篇法语的文章而遗憾,写那篇文章的人正在为没学好英语而犯愁。如果英文尚未精通,暂且不要去学二外。…
View More [转]如何提高科研能力和学术水平Grouping and Sorting in R
Basically, using R I would like to take a data set that looks like this: And transform it to look like this: Notice that the…
View More Grouping and Sorting in RTranspose column to row
Select to suit, Search, Replace \r\n with ‘space’ (using Extended). Notepad ++ puts a carriage return and a line feed at the end of each…
View More Transpose column to rowTricks with Notepad++
Notepad++ is an amazing text editor which not just gives you option to edit and save your text files, but also gives lot many features…
View More Tricks with Notepad++R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate vs
R has many *apply functions which are ably described in the help files (e.g. ?apply). There are enough of them, though, that beginning useRs may have…
View More R Grouping functions: sapply vs. lapply vs. apply. vs. tapply vs. by vs. aggregate vsMapping Data You Already Have
There are many interesting and effective ways to map data that you may already have from various sources. Whether that data comes from human beings,…
View More Mapping Data You Already HaveINTEGRATING ARCGIS AND GOOGLE EARTH FOR CRIME ANALYSIS
BY ERIC PIMPLER GOOGLE EARTH ’m going to be taking a slightly different approach in this post than I have in previous posts. Typically, GeoChalkboard focuses…
View More INTEGRATING ARCGIS AND GOOGLE EARTH FOR CRIME ANALYSIS