R在`[.data.frame`（group1.raw ,,＆＃34; 20130301＆＃34;）中不断给出错误：选择了未定义的列

Question

group1.raw <- merge(tic1[1], getYahooData(i, 20130301, 20160301, adjust = TRUE)[,"Close"])} 
colnames(group1.raw) <- c("tic1") 
group1.aggregated <- xts(group1.raw%%(1 / as.vector(group1.raw [, "20130301"])), 
    order.by <- index(group1.raw)) 
group1.port <- diff(log(group1.aggregated))       

R一直给我这个

Error in `[.data.frame`(group1.raw, , "20130301") :    undefined columns selected 

我错过了什么？