使用 ofstream 在 cython 中写下 2-D 向量

我用cython编写了一个class，它使用c ++中的vector来创建二维数组。我目前的问题是，我想write和read我的数组/矩阵的内容到文本文件中和从文本文件中。我想让矩阵的每一行都写在同一行中。我也想知道我如何给每个写入值一个format？

矩阵.pyx

from libcpp.vector cimport vector
import cython
import numpy as np
import ctypes
cimport numpy as np
cimport cython                                               
from libcpp.string cimport string    
cdef extern from "<iostream>" namespace "std" nogil:
cdef cppclass ostream:
ostream& write(const char*, int) except +
cdef cppclass istream:
istream& read(const char*, int) except +
cdef cppclass ifstream(istream):
ifstream(const char *) except +              
cdef extern from "<fstream>" namespace "std" nogil:         
cdef cppclass filebuf:
pass            
cdef cppclass fstream:
void close()
bint is_open()
void open(const char*, openmode)
void open(const char&, openmode)
filebuf* rdbuf() const
filebuf* rdbuf(filebuf* sb)              
cdef cppclass ofstream(ostream):
ofstream(const char*) except +
ofstream(const char*, openmode) except+
cdef cppclass ifstream(istream):
ifstream(const char*) except +
ifstream(const char*, openmode) except+              
cdef extern from "<iostream>" namespace "std::ios_base" nogil:
cdef cppclass openmode:
pass
cdef open_mode binary    
cdef extern from "<iterator>" namespace "std" nogil:
cdef cppclass ostream_iterator[T,charT,traits](iterator[output_iterator_tag, void, void, void, void]):
basic_ostream[charT,traits]* out_stream
ctypedef charT char_type
ctypedef traits traits_type
ctypedef basic_ostream[charT,traits] ostream_type
ostream_iterator (ostream_type& )
ostream_iterator (ostream_type& , const charT* )
cdef class Matrix:
def __cinit__(self, int rows=0, int columns=0):
self._rows=rows
self._columns=columns
self.matrix=new vector[double]()
self.matrix.resize(rows*columns)
def __dealloc__(self):
del self.matrix
@cython.boundscheck(False)
@cython.wraparound(False)
cpdef double getVal(self, int r, int c):
return self.matrix[0][r*self._columns+c]
@cython.boundscheck(False)
@cython.wraparound(False)
cpdef void setVal(self, int r, int c, double v): 
self.matrix[0][r*self._columns+c] = v
@cython.boundscheck(False)
@cython.wraparound(False)
cpdef void _write(self, char *filename):
cdef ofstream* outputter
outputter = new ofstream(filename, binary)
cdef int j
cdef ostream_iterator[double] os(outputter," ")
cdef ostream_iterator[double] oi(outputter,"n")
for j from 0 <= j < self._rows:
copy(self.matrix.begin()+ j*self._columns,self.matrix.begin()+ (j+1)*self._columns,os)
copy(self.matrix.begin(),self.matrix.begin(),oi)

矩阵.pxd

from libcpp.vector cimport vector
cdef class Matrix:
cdef vector[double] *matrix   
cdef int _rows
cdef int _columns
cpdef double getVal(self, int r, int c)
cpdef void setVal(self, int r, int c, double v)
cpdef void _write(self, char *filename)

错误消息是：

cdef ofstream out1(filename)
cdef int j
cdef ostream_iterator[double] os(out1," ")
^
------------------------------------------------------------
matrix.pyx:: Expected an identifier, found 'BEGIN_STRING'
Error compiling Cython file:
------------------------------------------------------------
...
cdef ofstream out1(filename)
cdef int j
cdef ostream_iterator[double] os(out1," ")
^
------------------------------------------------------------
matrix.pyx:: Expected ')', found 'CHARS'

任何使此代码工作的建议将不胜感激。

更新：

基于@DavidW答案，我编写了以下函数，以便将文件读入matrix对象。

from libcpp.string cimport string
cdef extern from "<sstream>" namespace "std" nogil:
cdef cppclass istringstream(istream):
istringstream() except +
istringstream(const string&) except +
void str(const string&)
cdef class Matrix:
def __cinit__(self, size_t rows=0, size_t columns=0):
self._rows=rows
self._columns=columns
self.matrix=new vector[double]()
self.matrix.resize(rows*columns)   

cpdef void _read(self, str filename):
cdef ifstream* infile = new ifstream(filename)
cdef string line
cdef size_t i = 0
cdef size_t columns = 0
while (getline(infile[0], line, 'n')):
istringstream iss(line)                  
self.matrix.insert(self.matrix.begin()+i*columns,istream_iterator[double](line),istream_iterator[double]())
if (i==0):
columns= self.matrix.size()
del infile
return