我还是R的初学者，我有一个问题！
我有222.000个观察数据框，我很有意思的是一个名为id的特定列。问题是它可以在同一个字符串中用'，'分隔，并且我想计算每个字符串中的唯一元素（我的意思是在第一个数据帧的每个字符串中）。 例如：
id results
0000001,0000003 2
0000002,0000002 1
0010001,0001006,0010001 2
我已经使用函数'str_split_fixed'来分隔同一个字符串中的所有id，并将结果放在一个新的数据框中（因此我知道我只有1个字符串的字符串或字符串中没有任何内容）。问题是可能多达68'，所以新的数据框架很大，有68个柱和220,000个观测值，需要很长时间（可能有15个秒）。使用了apply函数后知道所有的独特之处。
有人知道更有效的方式还是有想法？
最后，我使用了以下代码：
sapply(id, function(x)
length( # count items
unique( # that are unique
scan( # when arguments are presented to scan as text
text=x, what="", sep =",", # when separated by ","
quiet=TRUE))) )
但是有一条消息错误：
Error in textConnection(text, encoding = "UTF-8") :
argument 'text' incorrect
6 textConnection(text, encoding = "UTF-8")
5 scan(text = x, what = "", sep = ",", quiet = TRUE)
4 unique(scan(text = x, what = "", sep = ",", quiet = TRUE))
3 FUN(X[[i]], ...)
2 lapply(X = X, FUN = FUN, ...)
1 sapply(id, function(x) length(unique(scan(text = x,
what = "", sep = ",", quiet = TRUE))))
我的R版本是：
R version 3.2.2 (2015-08-14)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.10.5 (Yosemite)
locale:
[1] fr_FR.UTF-8/fr_FR.UTF-8/fr_FR.UTF-8/C/fr_FR.UTF-8/fr_FR.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] stringr_1.0.0 plyr_1.8.3
loaded via a namespace (and not attached):
[1] magrittr_1.5 tools_3.2.2 Rcpp_0.12.2 stringi_1.0-1
>
我试过这个：Encoding(id) <- "UTF-8"
但结果是：
Error in `Encoding<-`(`*tmp*`, value = "UTF-8")
，dput（id）的输出来自：
[9987,] "2320212,2320230"
[9988,] "4530090,4530917"
[9989,] "8532412"
[9990,] "4560292"
[9991,] "4540375"
[9992,] "3311324"
[9993,] "4540030"
[9994,] "9010000"
[9995,] "2811810"
[9996,] "3311000"
[9997,] "4540030"
[9998,] "4540215"
[9999,] "1541201"
[10000,] "2423810"
[ getOption("max.print") est atteint -- 90000 lignes omises ]
输出很大，所以我只发布结尾和第一行：
[9002,] "9460000"
和dput( head(data$id) )：
"9460000,9433000", "9460000,9436000", "9460000,9437000",
"9510000", "9510010", "9510030", "9510090", "9910000", "9910020",
"9910040", "9910090", "D", "FIELD_NOT_FOUND", "I"), class = "factor")
先谢谢你，杰夫
答案 0 :(得分：1)
sapply(id, function(x)
length( # count items
unique( # that are unique
scan( # when arguments are presented to scan as text
text=x, what="", sep =",", # when separated by ","
quiet=TRUE))) )
# --- result: first typed line is 'names' of the items, not the results.
1 2,3,4 1,1
1 3 1
参数text=x应允许scan接受长度为1的字符元素，并将其分解为分隔符参数值的分区中的组件。这些将从id向量逐个元素传递给匿名函数（如果它来自数据帧，则逐行传递）。