While I'm here, what's the good way to get a column slice? Say the
moral equivalent of matrix(...)[,:4], which gets the first four
columns?
Nick
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# HG changeset patch
# User Nick Alexander <[EMAIL PROTECTED]>
# Date 1179421831 25200
# Node ID c8546f05d767ee75c5eb1ed2f4e27394b090927d
# Parent 67cb892cac3a2fd39f5e9e5e3dd080418f5ad330
Migrate __getslice__ to a unified __getitem__ in sage.matrix.Matrix.
This fixes bug in matrix(...)[1:], which dropped the last row.
diff -r 67cb892cac3a -r c8546f05d767 sage/matrix/matrix0.pyx
--- a/sage/matrix/matrix0.pyx Wed May 02 20:11:25 2007 -0700
+++ b/sage/matrix/matrix0.pyx Thu May 17 10:10:31 2007 -0700
@@ -464,18 +464,19 @@ cdef class Matrix(sage.structure.element
def __iter__(self):
return matrix_misc.row_iterator(self)
- def __getitem__(self, ij):
- """
- Return element or row of self.
+ def __getitem__(self, key):
+ """
+ Return element, row, or slice of self.
INPUT:
- ij -- tuple (i,j) with i, j integers
- or
- ij -- integer
+ key -- tuple (i,j) with i, j integers
+ or key -- integer
+ or key -- slice object, created via [i:j]
USAGE:
- A[i, j] -- the i,j of A, and
- A[i] -- the i-th row of A.
+ A[i, j] -- the i,j of A, or
+ A[i] -- the i-th row of A, or
+ A[i:j] -- the i-th through (j-1)-st rows of A.
EXAMPLES:
sage: A = Matrix(Integers(2006),2,2,[-1,2,3,4])
@@ -500,44 +501,41 @@ cdef class Matrix(sage.structure.element
Traceback (most recent call last):
...
IndexError: matrix index out of range
- """
- cdef Py_ssize_t i, j
- cdef object x
-
- if PyTuple_Check(ij):
- # ij is a tuple, so we get i and j efficiently, construct corresponding integer entry.
- if PyTuple_Size(ij) != 2:
- raise IndexError, "index must be an integer or pair of integers"
- i = <object> PyTuple_GET_ITEM(ij, 0)
- j = <object> PyTuple_GET_ITEM(ij, 1)
- self.check_bounds(i, j)
- return self.get_unsafe(i, j)
- else:
- # If ij is not a tuple, coerce to an integer and get the row.
- i = ij
- return self.row(i)
-
- def __getslice__(self, Py_ssize_t i, Py_ssize_t j):
- """
- Returns a submatrix of this matrix got from the i-th through j-th rows.
-
- USAGE:
- A[i:j] -- return submatrix from those rows.
-
- EXAMPLES:
+
sage: n=10;a=matrix(QQ,n,range(n^2))
sage: a[0:3]
[ 0 1 2 3 4 5 6 7 8 9]
[10 11 12 13 14 15 16 17 18 19]
- [20 21 22 23 24 25 26 27 28 29]
- """
- if i < 0: i = self._nrows + i
- if j < 0: j = self._nrows + j
- if i >= self._nrows:
- i = self._nrows - 1
- if j >= self._nrows:
- j = self._nrows - 1
- return self.matrix_from_rows(range(i,j))
+ [20 21 22 23 24 25 26 27 28 29]
+ sage: a[:2]
+ [ 0 1 2 3 4 5 6 7 8 9]
+ [10 11 12 13 14 15 16 17 18 19]
+ sage: a[8:]
+ [80 81 82 83 84 85 86 87 88 89]
+ [90 91 92 93 94 95 96 97 98 99]
+
+ sage: a[9]
+ (90, 91, 92, 93, 94, 95, 96, 97, 98, 99)
+ sage: a[-1]
+ (90, 91, 92, 93, 94, 95, 96, 97, 98, 99)
+ """
+ cdef Py_ssize_t i, j
+ cdef object x
+
+ if PyTuple_Check(key):
+ # key is a tuple, so we get i and j efficiently, construct corresponding integer entry.
+ if PyTuple_Size(key) != 2:
+ raise IndexError, "index must be an integer or pair of integers"
+ i = <object> PyTuple_GET_ITEM(key, 0)
+ j = <object> PyTuple_GET_ITEM(key, 1)
+ self.check_bounds(i, j)
+ return self.get_unsafe(i, j)
+ elif isinstance(key, slice):
+ # Slice interpretation is passed to the sequence constructed by range
+ return self.matrix_from_rows(range(0, self._nrows).__getitem__(key))
+ else:
+ # If key is not a tuple, coerce to an integer and get the row.
+ return self.row(int(key))
def __setitem__(self, ij, x):
"""
