1. 图片说明
2. 例子
示例数据：
set.seed(123)dat = data.frame(ID = paste0("ID_",1:10),y1 = rnorm(10),y2=rnorm(10),y3=rnorm(10),y4 = rnorm(10))dat结果
> dat ID y1 y2 y3 y41 ID_1 -0.56047565 1.2240818 -1.0678237 0.426464222 ID_2 -0.23017749 0.3598138 -0.2179749 -0.295071483 ID_3 1.55870831 0.4007715 -1.0260044 0.895125664 ID_4 0.07050839 0.1106827 -0.7288912 0.878133495 ID_5 0.12928774 -0.5558411 -0.6250393 0.821581086 ID_6 1.71506499 1.7869131 -1.6866933 0.688640257 ID_7 0.46091621 0.4978505 0.8377870 0.553917658 ID_8 -1.26506123 -1.9666172 0.1533731 -0.061911719 ID_9 -0.68685285 0.7013559 -1.1381369 -0.3059626610 ID_10 -0.44566197 -0.4727914 1.2538149 -0.380471003. 变为三列：ID，trait，y：melt
代码
re1 = melt(data = dat,id.vars=c("ID"),variable.name="Loc",value.name="y")head(re1)结果预览
> head(re1) ID Loc y1 ID_1 y1 -0.560475652 ID_2 y1 -0.230177493 ID_3 y1 1.558708314 ID_4 y1 0.070508395 ID_5 y1 0.129287746 ID_6 y1 1.715064994. 三列变为去：dcast
代码
dcast(data=re1,ID ~Loc)结果
> dcast(data=re1,ID ~Loc)Using 'y' as value column. Use 'value.var' to override ID y1 y2 y3 y41 ID_1 -0.56047565 1.2240818 -1.0678237 0.426464222 ID_10 -0.44566197 -0.4727914 1.2538149 -0.380471003 ID_2 -0.23017749 0.3598138 -0.2179749 -0.295071484 ID_3 1.55870831 0.4007715 -1.0260044 0.895125665 ID_4 0.07050839 0.1106827 -0.7288912 0.878133496 ID_5 0.12928774 -0.5558411 -0.6250393 0.821581087 ID_6 1.71506499 1.7869131 -1.6866933 0.688640258 ID_7 0.46091621 0.4978505 0.8377870 0.553917659 ID_8 -1.26506123 -1.9666172 0.1533731 -0.0619117110 ID_9 -0.68685285 0.7013559 -1.1381369 -0.305962665.命令解析
melt(dat,c("ID","Loc"))> ex1 = data.frame(Cul = rep(1:10,2),Loc=rep(1:2,each=10),rep1=rnorm(20),rep2=rnorm(20),rep3=rnorm(20))> head(ex1)Cul Loc rep1 rep2 rep31 1 1 -0.71040656 0.1176466 0.70178432 2 1 0.25688371 -0.9474746 -0.26219753 3 1 -0.24669188 -0.4905574 -1.57214424 4 1 -0.34754260 -0.2560922 -1.51466775 5 1 -0.95161857 1.8438620 -1.60153626 6 1 -0.04502772 -0.6519499 -0.5309065> ex1_re = melt(ex1,c("Cul","Loc"))> head(ex1_re)Cul Loc variable value1 1 1 rep1 -0.710406562 2 1 rep1 0.256883713 3 1 rep1 -0.246691884 4 1 rep1 -0.347542605 5 1 rep1 -0.951618576 6 1 rep1 -0.04502772ex1_re如果想要变回去，用dcast(ex1_re, Cul + Loc ~ variable), ~号左边是保持不变的列名，~右边是需要扩展的列名， 省略的value是需要填充的数据。> dcast(ex1_re,Cul+Loc~variable) Cul Loc rep1 rep2 rep31 1 1 -0.71040656 0.11764660 0.70178432 1 2 -0.57534696 1.44455086 0.78773883 2 1 0.25688371 -0.94747461 -0.26219754 2 2 0.60796432 0.45150405 0.76904225 3 1 -0.24669188 -0.49055744 -1.57214426 3 2 -1.61788271 0.04123292 0.33220267 4 1 -0.34754260 -0.25609219 -1.51466778 4 2 -0.05556197 -0.42249683 -1.00837669 5 1 -0.95161857 1.84386201 -1.601536210 5 2 0.51940720 -2.05324722 -0.119452611 6 1 -0.04502772 -0.65194990 -0.530906512 6 2 0.30115336 1.13133721 -0.280395313 7 1 -0.78490447 0.23538657 -1.461755614 7 2 0.10567619 -1.46064007 0.562989515 8 1 -1.66794194 0.07796085 0.687916816 8 2 -0.64070601 0.73994751 -0.372438817 9 1 -0.38022652 -0.96185663 2.100108918 9 2 -0.84970435 1.90910357 0.976973419 10 1 0.91899661 -0.07130809 -1.2870305关注我
ID：R-breeding公众号：育种数据分析之放飞自我
