使用magic.wand函数来代码块 [英] Using the magic.wand function for a block of code
问题描述
我想使用plyrmr包,同时保留我现有的代码写在dplyr中,因此我想使用magic.wand函数。我使用mtcars数据集为简单起见,它的路径是HDFS(Hadoop分布式文件系统)上的/ user / sgerony / mtcars2。
代码块包含基本函数,但也包含dplyr函数,这是我的代码:
magic.wand(rename,TRUE)
filename< - / user / sgerony / mtcars
complex.function = function(x){
x $ carb < - x [,ncol(x)] * 2
x $ carb< - x $ carb + 2
x< - as.data.frame(rename(x,lol = carb))
return(x)
}
magic.wand(complex.function)
#不工作
输入(filename)%|%complex.function()
结果(注意:行名已解除)
mpg cyl disp hp drat wt qsec vs am gear lol
1 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 10
2 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 10
3 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 4
4 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 4
5 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 6
6 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 4
7 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 10
8 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 6
9 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 6
10 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 10
11 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 10
12 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 8
13 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 8
14 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 8
15 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 10
16 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 10
17 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 10
18 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 4
19 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 6
20 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 4
21 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 4
22 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 6
23 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 6
24 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 10
25 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 6
26 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 4
27 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 6
28 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 6
29 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 10
30 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 14
31 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 18
32 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 6
问题1:这是正确的做法吗?意思是我必须首先调用magic.wand的dplyr函数,然后为代码块?
问题2:为什么我不能调用magic.wand这样的功能?
magic.wand(dplyr :: rename,TRUE)
结果:
> magic.wand(dplyr :: rename,TRUE)
match.fun中的错误(paste(f.name,_)):
'paste0(c(::,dplyr ,rename),_)'不是函数,字符或符号
详细信息:它创建名称::,::。data.frame,::。default,plyr,rename的功能
Isn'有必要确保我们不使用几个库中包含的函数吗?
问题3:为什么我必须将TRUE作为第二个参数第一个魔术棒,而不是最后一个?
filename< - / user / sgerony / mtcars
magic.wand(重命名,TRUE)
filename < - / user / sgerony / mtcars
complex.function = function(x){
x $ carb < - x [,ncol (x)= $($)
x $ carb $ x $ carb $ $)))))))))))))))))))))))))))
}
magic.wand(complex.function,TRUE)
错误:
get(as.character(FUN),mode =funct离子,envir = envir):
对象'complex.function''模式'function'未找到
问题4:如果我的代码块正在使用dplyr管道操作员怎么办?即:
complex.function = function(x){
x $ carb< - x [,ncol )] * 2
x $ carb< - x $ carb + 2
x< - as.data.frame(x%>%rename(lol = carb))
return )
}
我应该用plyrmr管道操作符替换%>% ?即%|%?
问题5:我应该在dplyr函数上调用magic.wand函数,这些函数等同于plyrmr函数,如group_by?
问题6:为什么在使用asPOSIXct时出现错误?
magic.wand(mutate,TRUE)
filename< - / user / sgerony / mtcars
complex.function = function(x){
x $ carb < ncol(x)] * 2
x $ carb< - x $ carb + 2
x< - as.data.frame(mutate(x,date.time = as.POSIXct(2014-01 -01 03:15)))
return(x)
}
magic.wand(complex.function)
#Works
mtcars% |%complex.function()
#不工作
input(filename)%|%complex.function()
我意识到这是一个很大的问题,所以感谢您的帮助
- a。不,错误消息显示。
b。否。 - a。为什么不?
b。不,在其他地方,有很多关于命名空间的解释。 -
help(magic.wand)
解释。如果你告诉我,由于某种原因我不清楚,我会尝试做得更好,但是切割和粘贴Rd文档是违反规则的。 - 它应该可以工作,但我不会支持它。
- plyrmr中有本机功能,可以执行什么dplyr函数(并已经使用它们)。
magic.wand
的正确用法是使自定义函数像complex.functions
hadoop-aware。 - 这与
plyrmr
无关,最好的方法是发布一个单独的问题。
让我试一试:
complex.function = function(x){
x $ carb< - x [,ncol(x)] * 2
x $ carb< - x $ carb + 2
重命名(x,lol =碳)}
魔术。 wand(complex.function)
input(mtcars)%|%complex.function
请注意:只需要一个 magic.wand
需要调用(另一个不应该受伤,但是多余),而从 complex.function
。为我工作。
I want to use the plyrmr package while keeping my existent code written in dplyr and thus I want to use the "magic.wand" function. I am using the "mtcars" dataset for simplicity and the the path to it is "/user/sgerony/mtcars2" on the HDFS (Hadoop Distributed File System).
The block of code contains base functions but also dplyr functions and this is my code:
magic.wand(rename,TRUE)
filename <- "/user/sgerony/mtcars"
complex.function = function(x){
x$carb <- x[,ncol(x)]*2
x$carb <- x$carb+2
x <- as.data.frame(rename(x, lol=carb))
return(x)
}
magic.wand(complex.function)
# does NOT work
input(filename) %|% complex.function()
Result (Note: Row names have dissapeared)
mpg cyl disp hp drat wt qsec vs am gear lol
1 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 10
2 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 10
3 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 4
4 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 4
5 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 6
6 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 4
7 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 10
8 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 6
9 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 6
10 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 10
11 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 10
12 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 8
13 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 8
14 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 8
15 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 10
16 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 10
17 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 10
18 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 4
19 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 6
20 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 4
21 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 4
22 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 6
23 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 6
24 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 10
25 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 6
26 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 4
27 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 6
28 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 6
29 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 10
30 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 14
31 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 18
32 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 6
Question 1: Is this the right way to do? meaning do I have to call a first time the magic.wand for the dplyr functions and then for the bloc of code?
Question 2: Why can't I call the magic.wand function like this?
magic.wand(dplyr::rename,TRUE)
Result:
> magic.wand(dplyr::rename,TRUE)
Error in match.fun(paste0(f.name, "_")) :
'paste0(c("::", "dplyr", "rename"), "_")' is not a function, character or symbol
Details: It creates functions of names "::","::.data.frame","::.default","plyr","rename"
Isn't it necessary to be sure that we are not using functions contained in several libraries?
Question 3: Why do I have to put "TRUE" as a second argument of the first magic.wand call and not the last one?
filename<-"/user/sgerony/mtcars"
magic.wand(rename,TRUE)
filename <- "/user/sgerony/mtcars"
complex.function = function(x){
x$carb <- x[,ncol(x)]*2
x$carb <- x$carb+2
x <- as.data.frame(rename(x, lol=carb))
return(x)
}
magic.wand(complex.function,TRUE)
Error:
Error in get(as.character(FUN), mode = "function", envir = envir) :
object 'complex.function_' of mode 'function' was not found
Question 4: What if my block of code is using the dplyr piping operator? namely:
complex.function = function(x){
x$carb <- x[,ncol(x)]*2
x$carb <- x$carb+2
x <- as.data.frame(x %>% rename(lol=carb))
return(x)
}
Should I just replace the "%>%" by the plyrmr piping operator? Namely "%|%"?
Question 5: Should I call the magic.wand function on dplyr functions that are equivalent to plyrmr functions like "group_by"?
Question 6: Why do I have an error when using as.POSIXct?
magic.wand(mutate,TRUE)
filename <- "/user/sgerony/mtcars"
complex.function = function(x){
x$carb <- x[,ncol(x)]*2
x$carb <- x$carb+2
x <- as.data.frame(mutate(x,date.time=as.POSIXct("2014-01-01 03:15")))
return(x)
}
magic.wand(complex.function)
#Works
mtcars %|% complex.function()
# does NOT work
input(filename) %|% complex.function()
I realize this is a big question, so thanks for trying to help
- a. No, as the error message shows. b. No.
- a.Why not? b. No. There's plenty of explanations about namespaces in R elsewhere.
help(magic.wand)
explains that. If you told me it's unclear for some reason, I'd try to do better, but cutting and pasting Rd docs is against the rules.- It should work, but I am not going to support it.
- There are native functions in plyrmr that do what dplyr functions do (and use them already). The right use for
magic.wand
is to make custom functions likecomplex.functions
hadoop-aware. - That's unrelated to
plyrmr
, your best bet is to post a separate question.
Let me give it a try:
complex.function = function(x){
x$carb <- x[,ncol(x)]*2
x$carb <- x$carb+2
rename(x, lol=carb)}
magic.wand(complex.function)
input(mtcars) %|% complex.function
Please note: only one magic.wand
call needed (the other one shouldn't hurt, but redundant) and some crud removed from complex.function
. Works for me.
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