read.csv() - two out of three columns [duplicate]

问题

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Closed 8 years ago.

Possible Duplicate:
Only read limited number of columns in R

I have a ascii-dataset which consists of three columns, but only the last two are actual data. Now I want to dotchart the data by using read.csv(file = "result1", sep= " "). R reads all three columns. How do I avoid this?

回答1:

You can use the colClasses argument to skip columns:

mydata <- read.csv('mydata.csv', colClasses=c('NULL',NA,NA))

or

mydata <- read.csv('mydata.csv', colClasses=c('NULL', 'numeric', 'numeric'))

来源：https://stackoverflow.com/questions/7714997/read-csv-two-out-of-three-columns