在从文本文件读取数据到数据框时,您可以使用colClasses
参数指定每列的类型。下面是我电脑上有的一个文件:
> head(read.csv("R/Data/ZipcodeCount.csv"))
X zipcode stateabb countyno countyname
1 1 401 NY 119 WESTCHESTER
2 391 501 NY 103 SUFFOLK
3 392 544 NY 103 SUFFOLK
4 393 601 PR 1 ADJUNTAS
5 630 602 PR 3 AGUADA
6 957 603 PR 5 AGUADILLA
> head(read.csv("R/Data/ZipcodeCount.csv",colClasses=c(rep("factor",5))))
X zipcode stateabb countyno countyname
1 1 00401 NY 119 WESTCHESTER
2 391 00501 NY 103 SUFFOLK
3 392 00544 NY 103 SUFFOLK
4 393 00601 PR 001 ADJUNTAS
5 630 00602 PR 003 AGUADA
6 957 00603 PR 005 AGUADILLA
> zip<-read.csv("R/Data/ZipcodeCount.csv",colClasses=c(rep("factor",5)))
> str(zip)
'data.frame': 53424 obs. of 5 variables:
$ X : Factor w/ 53424 levels "1","10000081",..: 1 36316 36333 36346 43638 52311 19581 23775 26481 26858 ...
$ zipcode : Factor w/ 41174 levels "00401","00501",..: 1 2 3 4 5 6 6 7 8 9 ...
$ stateabb : Factor w/ 60 levels ""," ","AK","AL",..: 41 41 41 46 46 46 46 46 46 46 ...
$ countyno : Factor w/ 380 levels "","000","001",..: 106 95 95 3 5 7 5 7 7 9 ...
$ countyname: Factor w/ 1925 levels "","ABBEVILLE",..: 1844 1662 1662 9 10 11 10 11 11 12 ...
> head(table(zip[,"zipcode"]))
00401 00501 00544 00601 00602 00603
1 1 1 1 1 2
正如您所看到的,R不再将邮政编码视为数字,而是将其视为因子。在您的情况下,您需要指定前6列的类,然后选择第7列的factor
。因此,如果前6列是数字,则应该像这样指定:colClasses = c(rep("numeric",6),"factor")
。
r
,可以找到R
。 - Grijesh Chauhanr
和R
是一样的吗? - Grijesh Chauhan