我正在通过黑客机器学习,我被困在这一行:
from.weight <- ddply(priority.train, .(From.EMail), summarise, Freq = length(Subject))
这会产生以下错误:
Error in attributes(out) <- attributes(col) :
'names' attribute [9] must be the same length as the vector [1]
这是一个追溯():
> traceback()
11: FUN(1:5[[1L]], ...)
10: lapply(seq_len(n), extract_col_rows, df = x, i = i)
9: extract_rows(x$data, x$index[[i]])
8: `[[.indexed_df`(pieces, i)
7: pieces[[i]]
6: function (i)
{
piece <- pieces[[i]]
if (.inform) {
res <- try(.fun(piece, ...))
if (inherits(res, "try-error")) {
piece <- paste(capture.output(print(piece)), collapse = "\n")
stop("with piece ", i, ": \n", piece, call. = FALSE)
}
}
else {
res <- .fun(piece, ...)
}
progress$step()
res
}(1L)
5: .Call("loop_apply", as.integer(n), f, env)
4: loop_apply(n, do.ply)
3: llply(.data = .data, .fun = .fun, ..., .progress = .progress,
.inform = .inform, .parallel = .parallel, .paropts = .paropts)
2: ldply(.data = pieces, .fun = .fun, ..., .progress = .progress,
.inform = .inform, .parallel = .parallel, .paropts = .paropts)
1: ddply(priority.train, .(From.EMail), summarise, Freq = length(Subject))
priority.train对象是一个数据框,这里有更多信息:
> mode(priority.train)
[1] "list"
> names(priority.train)
[1] "Date" "From.EMail" "Subject" "Message" "Path"
> sapply(priority.train, mode)
Date From.EMail Subject Message Path
"list" "character" "character" "character" "character"
> sapply(priority.train, class)
$Date
[1] "POSIXlt" "POSIXt"
$From.EMail
[1] "character"
$Subject
[1] "character"
$Message
[1] "character"
$Path
[1] "character"
> length(priority.train)
[1] 5
> nrow(priority.train)
[1] 1250
> ncol(priority.train)
[1] 5
> str(priority.train)
'data.frame': 1250 obs. of 5 variables:
$ Date : POSIXlt, format: "2002-01-31 22:44:14" "2002-02-01 00:53:41" "2002-02-01 02:01:44" "2002-02-01 10:29:23" ...
$ From.EMail: chr "removed@removed.ca" "removed@removed.net" "removed@removed.ca" "removed@removed.net" ...
$ Subject : chr "please help a newbie compile mplayer :-)" "re: please help a newbie compile mplayer :-)" "re: please help a newbie compile mplayer :-)" "re: please help a newbie compile mplayer :-)" ...
$ Message : chr " \n Hello,\n \n I just installed redhat 7.2 and I think I have everything \nworking properly. Anyway I want to in"| __truncated__ "Make sure you rebuild as root and you're in the directory that you\ndownloaded the file. Also it might complain of a few depen"| __truncated__ "Lance wrote:\n\n>Make sure you rebuild as root and you're in the directory that you\n>downloaded the file. Also it might compl"| __truncated__ "Once upon a time, rob wrote :\n\n> I dl'd gcc3 and libgcc3, but I still get the same error message when I \n> try rpm --rebuil"| __truncated__ ...
$ Path : chr "../03-Classification/data/easy_ham/01061.6610124afa2a5844d41951439d1c1068" "../03-Classification/data/easy_ham/01062.ef7955b391f9b161f3f2106c8cda5edb" "../03-Classification/data/easy_ham/01063.ad3449bd2890a29828ac3978ca8c02ab" "../03-Classification/data/easy_ham/01064.9f4fc60b4e27bba3561e322c82d5f7ff" ...
Warning messages:
1: In encodeString(object, quote = "\"", na.encode = FALSE) :
it is not known that wchar_t is Unicode on this platform
2: In encodeString(object, quote = "\"", na.encode = FALSE) :
it is not known that wchar_t is Unicode on this platform
我会发布一个样本,但内容有点长,我不认为这里的内容是相关的 .
这里也会发生同样的错误:
> ddply(priority.train, .(Subject))
Error in attributes(out) <- attributes(col) :
'names' attribute [9] must be the same length as the vector [1]
有没有人知道这里发生了什么?错误似乎是由priority.train之外的其他对象生成的,因为它的names属性显然有9个元素 .
我很感激任何帮助 . 谢谢!
Problem solved
由于@ user1317221_G使用dput功能的提示,我发现了这个问题 . 问题在于Date字段,此时此列表包含9个字段(sec,min,hour,mday,mon,year,wday,yday,isdst) . 为了解决这个问题,我只是将日期转换为字符向量,使用ddply然后将日期转换回日期:
> tmp <- priority.train$Date
> priority.train$Date <- as.character(priority.train$Date)
> from.weight <- ddply(priority.train, .(From.EMail), summarise, Freq = length(Subject))
> priority.train$Date <- tmp
> rm(tmp)
7 回答
我也面临同样的问题,我通过使用as.character保持ddply所需的数据并将过滤器变量和所有必需的Text变量转换为字符来解决它
有效
我通过将格式从POSIXlt转换为POSIXct来解决我遇到的问题,正如Hadley在上面建议的那样 - 一行代码:
你可能已经seen this并没有帮助 . 我想我们可能还没有回答,因为人们无法重现你的错误 .
dput
或更小的head(dput())
可能有助于此 . 但是这里有一个使用base
的替代方案:这
tapply
对你有用吗?你也可以尝试更简单:
我有一个非常相似的问题,虽然不确定它是否是一个相同的问题 . 我收到了以下错误 .
我在列表模式下没有任何变量,因此Mota的解决方案对我的情况不起作用 . 我排序问题的方法是删除plyr 1.8并手动安装plyr 1.7 . 然后错误就消失了 . 我也尝试重新安装plyr 1.8并重复了这个问题 .
HTH .
我也遇到了与ddply类似的问题,并给出了下面的代码/错误:
数据框“测试”中有相当多的分类变量 .
将分类变量转换为字符变量如下所示使ddply命令起作用:
一旦你理解了一个干扰你的日期列,你也可以在运行命令时将该列留下而不是转换它...
所以
可以变成
例如,如果POSIXlt日期恰好位于数据帧的第8列 . 报告错误的奇怪之处在于,它可能与您正在分组的内容或您要求的输出信息无关...
我在使用
ddply
时遇到了同样的问题并用doBy
修复了它