我相信在spark / python编程的上下文中,这是一个相当基本的操作。我有一个看起来像这样的文本文件:
dan@dan-laptop:~/workspace/scratch$ clang++ eigen_func_test.cpp -I /home/dan/Downloads/eigen_3.3.3/ --std=c++11 && ./a.out
In file included from eigen_func_test.cpp:2:
In file included from /home/dan/Downloads/eigen_3.3.3/Eigen/Core:436:
/home/dan/Downloads/eigen_3.3.3/Eigen/src/Core/PlainObjectBase.h:899:7: error: static_assert failed
"INVALID_MATRIX_TEMPLATE_PARAMETERS"
...EIGEN_STATIC_ASSERT((EIGEN_IMPLIES(MaxRowsAtCompileTime==1 && MaxColsAtCompileTime!=1, (Options&RowMajor)==RowMajor)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/dan/Downloads/eigen_3.3.3/Eigen/src/Core/util/StaticAssert.h:32:40: note: expanded from macro
'EIGEN_STATIC_ASSERT'
#define EIGEN_STATIC_ASSERT(X,MSG) static_assert(X,#MSG);
^ ~
/home/dan/Downloads/eigen_3.3.3/Eigen/src/Core/PlainObjectBase.h:535:7: note: in instantiation of member function
'Eigen::PlainObjectBase<Eigen::Matrix<double, 1, 3, 0, 1, 3> >::_check_template_params' requested here
_check_template_params();
^
/home/dan/Downloads/eigen_3.3.3/Eigen/src/Core/Matrix.h:379:9: note: in instantiation of function template
specialization 'Eigen::PlainObjectBase<Eigen::Matrix<double, 1, 3, 0, 1, 3>
>::PlainObjectBase<Eigen::Block<Eigen::Matrix<double, -1, 3, 0, -1, 3>, 1, 3, false> >' requested here
: Base(other.derived())
^
eigen_func_test.cpp:32:9: note: in instantiation of function template specialization 'Eigen::Matrix<double, 1, 3, 0,
1, 3>::Matrix<Eigen::Block<Eigen::Matrix<double, -1, 3, 0, -1, 3>, 1, 3, false> >' requested here
return f;
^
eigen_func_test.cpp:41:10: note: in instantiation of function template specialization
'func<Eigen::Block<Eigen::Matrix<double, -1, 3, 0, -1, 3>, 1, 3, false> >' requested here
cout << func( M.row(2) ) << endl;
^
1 error generated.
然后我使用以下代码读取文本文件:
mydata.txt
12 34 2.3 15
23 11 1.5 9
33 18 4.5 99
并将此文件作为字符串的RDD读入。但是,我想分离值并将它们全部转换为浮点数。所以我将上面的行更改为:
data = sc.textFile("mydata.txt")
成功按空格分割数据。然而,我正在努力想出地图函数,然后转换为浮点数。类似的东西:
data = sc.textFile("matrix1.txt").map(lambda line: line.split(' '))
但这没有用。任何帮助赞赏! 谢谢!
编辑 - 请假设我不知道数据的列数。所以.map(lambda line:float(line [0]),float(line [1]),float(line [2]),float(line [3]))的内容并不是特别有帮助。< / p>
答案 0 :(得分:0)
没关系,明白了。
.map(lambda line: [float(x) for x in line])