> install.packages('knitr')
--- 在此連線階段时请选用CRAN的鏡子 ---
还安装相依关系‘glue’, ‘stringi’, ‘stringr’, ‘yaml’


  有二进制版本的，但源代码版本是后来的:
        binary source needs_compilation
glue     1.0.0  1.3.0              TRUE
stringi  1.1.5  1.2.4              TRUE
stringr  1.2.0  1.3.1             FALSE
yaml    2.1.14  2.2.0              TRUE
knitr   1.15.1   1.21             FALSE

  Binaries will be installed
试开URL’https://mirrors.tuna.tsinghua.edu.cn/CRAN/bin/windows/contrib/3.2/glue_1.0.0.zip'
Content type 'application/zip' length 34947 bytes (34 KB)
downloaded 34 KB

试开URL’https://mirrors.tuna.tsinghua.edu.cn/CRAN/bin/windows/contrib/3.2/stringi_1.1.5.zip'
Content type 'application/zip' length 14220135 bytes (13.6 MB)
downloaded 13.6 MB

试开URL’https://mirrors.tuna.tsinghua.edu.cn/CRAN/bin/windows/contrib/3.2/yaml_2.1.14.zip'
Content type 'application/zip' length 180051 bytes (175 KB)
downloaded 175 KB

程序包‘glue’打开成功，MD5和检查也通过
程序包‘stringi’打开成功，MD5和检查也通过
程序包‘yaml’打开成功，MD5和检查也通过

下载的二进制程序包在
        C:\Users\AppData\Local\Temp\RtmpQRAPAq\downloaded_packages里
安装源码包‘stringr’, ‘knitr’

试开URL’https://mirrors.tuna.tsinghua.edu.cn/CRAN/src/contrib/stringr_1.3.1.tar.gz'
Content type 'application/x-gzip' length 119156 bytes (116 KB)
downloaded 116 KB

试开URL’https://mirrors.tuna.tsinghua.edu.cn/CRAN/src/contrib/knitr_1.21.tar.gz'
Content type 'application/x-gzip' length 699667 bytes (683 KB)
downloaded 683 KB

* installing *source* package 'stringr' ...
** 成功将'stringr'程序包解包并MD5和检查
** R
** data
*** moving datasets to lazyload DB
** inst
** preparing package for lazy loading
Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[]) :
  namespace 'stringi' 1.1.5 is being loaded, but >= 1.1.7 is required
ERROR: lazy loading failed for package 'stringr'
* removing 'E:/R-3.2.5/library/stringr'
ERROR: dependency 'stringr' is not available for package 'knitr'
* removing 'E:/R-3.2.5/library/knitr'

下载的程序包在
        ‘C:\Users\AppData\Local\Temp\RtmpQRAPAq\downloaded_packages’里
Warning messages:
1: 运行命令'"E:/R-3.2.5/bin/i386/R" CMD INSTALL -l "E:\R-3.2.5\library" C:\Users\AppData\Local\Temp\RtmpQRAPAq/downloaded_packages/stringr_1.3.1.tar.gz'的状态是1
2: In install.packages("knitr") : 安装程序包‘stringr’时退出狀態的值不是0
3: 运行命令'"E:/R-3.2.5/bin/i386/R" CMD INSTALL -l "E:\R-3.2.5\library" C:\Users\AppData\Local\Temp\RtmpQRAPAq/downloaded_packages/knitr_1.21.tar.gz'的状态是1
4: In install.packages("knitr") : 安装程序包‘knitr’时退出狀態的值不是0


过程如上所示，安装出现问题，不知道怎么解决，有人帮忙看一看么，非常感谢