attempt to use zero-length variable name


R version 3.2.2 (2015-08-14) -- "Fire Safety"
Copyright (C) 2015 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64 (64-bit)

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[Workspace loaded from ~/.RData]

> ```{r}
Error: attempt to use zero-length variable name
> library(abind)
> library(arm)
载入需要的程辑包：MASS
载入需要的程辑包：Matrix
载入需要的程辑包：lme4

arm (Version 1.8-6, built: 2015-7-7)

Working directory is C:/Users/17486/Documents

> library(caret)
载入需要的程辑包：lattice
载入需要的程辑包：ggplot2
>
> ```
Error: attempt to use zero-length variable name
> ## Loading required package: lattice
> ## Loading required package: ggplot2
>
> ```{r}
Error: attempt to use zero-length variable name
> library(kernlab)
> library(klaR)
> library(rattle)
载入需要的程辑包：RGtk2
Rattle: A free graphical interface for data mining with R.
XXXX 3.5.0 Copyright (c) 2006-2015 Togaware Pty Ltd.
键入'rattle()'去轻摇、晃动、翻滚你的数据。
> ```
Error: attempt to use zero-length variable name
> ## Rattle: A free graphical interface for data mining with R.
> ## Version 3.3.0 Copyright (c) 2006-2014 Togaware Pty Ltd.
> ## Type 'rattle()' to shake, rattle, and roll your data.
>
> ```{r}
Error: attempt to use zero-length variable name
> library(randomForest)
randomForest 4.6-12
Type rfNews() to see new features/changes/bug fixes.
> ```
Error: attempt to use zero-length variable name
> ## randomForest 4.6-10
> ## Type rfNews() to see new features/changes/bug fixes.
> ```{r}
Error: attempt to use zero-length variable name
> library(rpart)
> ```
Error: attempt to use zero-length variable name
>
> Seed for pseudo-random generator
Error: unexpected 'for' in "Seed for"
> ```{r}
Error: attempt to use zero-length variable name
> set.seed(12345)
> ```
Error: attempt to use zero-length variable name
> ```{r}
Error: attempt to use zero-length variable name
> library(abind)
> library(arm)
> library(caret)
>
> ```
Error: attempt to use zero-length variable name
> ## Loading required package: lattice
> ## Loading required package: ggplot2
>
> ```{r}
Error: attempt to use zero-length variable name
> library(kernlab)
> library(klaR)
> library(rattle)
> ```
Error: attempt to use zero-length variable name
> ## Rattle: A free graphical interface for data mining with R.
> ## Version 3.3.0 Copyright (c) 2006-2014 Togaware Pty Ltd.
> ## Type 'rattle()' to shake, rattle, and roll your data.
>
> ```{r}
Error: attempt to use zero-length variable name
> library(randomForest)
> ```
Error: attempt to use zero-length variable name
> ## randomForest 4.6-10
> ## Type rfNews() to see new features/changes/bug fixes.
> ```{r}
Error: attempt to use zero-length variable name
> library(rpart)
> ```
Error: attempt to use zero-length variable name
>
> Seed for pseudo-random generator
Error: unexpected 'for' in "Seed for"
> ```{r}
Error: attempt to use zero-length variable name
> set.seed(12345)
> Seed for pseudo-random generator
Error: unexpected 'for' in "Seed for"
> ```{r}
Error: attempt to use zero-length variable name
> set.seed(12345)
> ```
Error: attempt to use zero-length variable name
> ```{r}
Error: attempt to use zero-length variable name
> urlTrain <- "http://d396qusza40orc.cloudfront.net/predmachlearn/pml-training.csv"
> urlTest <- "http://d396qusza40orc.cloudfront.net/predmachlearn/pml-testing.csv"
> ```
Error: attempt to use zero-length variable name


这个不知道啥问题，请教高手，感谢！