R绘图的生物学家（2）：Importing data from

1. 需要用到的文件下载网址：

• http://hgdownload-test.soe.ucsc.edu/goldenPath/hg19/encodeDCC/wgEncodeBroadHmm/
• https://genome.ucsc.edu/cgi-bin/hgTables
• https://www.ensembl.org/Mus_musculus/Info/Index
• http://www.nature.com/onc/journal/v25/n15/suppinfo/1209254s1.html?url=/onc/journal/v25/n15/full/1209254a.html&foxtrotcallback=true

2. 代码解释

# 赋值文件名，这里我使用的是csv格式
filename <- "Lesson-02/micro_array_results_table1.csv"
# 写入数据框
my_data <- read.csv(filename, sep=",", header=TRUE)
head(my_data)
# 从几个网站下载需要的文件
# Where to find publicly available big data
# UCSC -- RefSeq genes from table browser
# Ensembl -- Mouse regulatory features MultiCell
# ENCODE -- HMM: wgEncodeBroadHmmGm12878HMM.bed

# 读取数据
genes <- read.csv("Lesson-02/RefSeq_Genes", sep="\t", header=TRUE)
head(genes)
# dim()函数用来查看行列数
dim(genes)

regulatory_features <- read.csv("Lesson-02/RegulatoryFeatures_MultiCell.gff", sep="\t", header=FALSE)
head(regulatory_features)
dim(regulatory_features)


chromHMM <- read.csv("Lesson-02/wgEncodeBroadHmmGm12878HMM.bed", sep="\t", header=FALSE)
head(chromHMM)
dim(chromHMM)

这一课比较简单，就是讲解数据的导入，语法也没有多少，主要就是赋值和读取。