r - 无法在 r 中安装 XML 包

Question

我正在尝试在 r 中安装“XML”包，但出现错误。
请告诉我哪里出了问题。

操作系统:OS X 10.11.6
R版本:3.3.2
执行 "install.packages("XML") 时的错误信息如下。

* installing *source* package ‘XML’ ...
** package ‘XML’ successfully unpacked and MD5 sums checked
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
checking for sed... /usr/bin/sed
checking for pkg-config... /usr/local/bin/pkg-config
checking for xml2-config... /usr/bin/xml2-config
USE_XML2 = yes
SED_EXTENDED_ARG: -E
Minor 9, Patch 2 for 2.9.2
Located parser file -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk/usr/include/libxml2/parser.h
Checking for 1.8:  -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk/usr/include/libxml2
Using libxml2.*
checking for gzopen in -lz... yes
checking for xmlParseFile in -lxml2... no
checking for xmlParseFile in -lxml... no
configure: error: "libxml not found"
ERROR: configuration failed for package ‘XML’

然后我设置了 LIBXML_INCDIR=/usr/local/Cellar/libxml2/2.9.4，然后再次尝试。
然后发生另一个错误。

* installing *source* package ‘XML’ ...
** package ‘XML’ successfully unpacked and MD5 sums checked
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
checking for sed... /usr/bin/sed
checking for pkg-config... /usr/local/bin/pkg-config
Checking directory of LIBXML_INCDIR
You specified LIBXML_INCDIR, but we couldn't find parser.h
Please specify it correctly and re-run the INSTALL'ation.
ERROR: configuration failed for package ‘XML’

还尝试使用 LIBXML_INCDIR=/usr/local/Cellar/libxml2/2.9.4/include
结果同上。

问候

Answer 1

这在 Mac OS X 10.11 中对我有用:

在终端中:

type xml2-config
xml2-config is /opt/local/bin/xml2-config

在 R 中:

Sys.setenv(XML_CONFIG="/opt/local/bin/xml2-config")