ArrayUtil.h
Classes
- Global Functions -- Split a String into its elements. (full description)
- Global Functions -- Concatenate two Arrays. (full description)
- Global Functions -- Reorder the axes of an array. (full description)
- Global Functions -- Helper function for function reorderArray.. (full description)
Interface
- Vector<String> stringToVector (const String& string, char delim = ',')
- Vector<String> stringToVector (const String& string, const Regex& delim)
Review Status
- Reviewed By:
- UNKNOWN
- Date Reviewed:
- before2004/08/25
- Programs:
- Tests:
Prerequisite
Etymology
stringToVector converts a String to a Vector of Strings.
Synopsis
The function stringToVector splits a string into its elements
using the given delimiter and returns them in a Vector<String>.
The default delimiter is a comma (,).
It is very useful when using a function taking a vector of strings
as shown in the example.
A more advanced way of splitting a string is by using a
regular expression as delimiter.
It makes it, for example, possible to treat whitespace around a comma
as part of the delimiter (as shown in an example below).
A string with length 0 results in a zero-length vector.
Motivation
As shown in the example, the function stringToVector makes
passing a Vector of Strings far easier.
Example
someFunction (stringToVector ("abc,def ,,gh"));
This results in a vector with 4 elements containing the values
"abc", "def ", "", and "gh". The vector is passed to someFunction.
This is far easier than having to do it as:
Vector<String> vector(4);
vector(0) = "abc";
vector(1) = "def ";
vector(2) = "";
vector(3) = "gh";
someFunction (vector);
The following example shows how to use a delimiter consisting of a comma
surrounded by possible whitespace.
Vector<String> result = stringToVector (source, Regex(" *, *"));
Example
Member Description
Interface
- Array<T> concatenateArray (const Array<T>& left, const Array<T>& right)
Review Status
- Reviewed By:
- UNKNOWN
- Date Reviewed:
- before2004/08/25
- Programs:
- Tests:
Prerequisite
Etymology
concatenateArray concatenates two Arrays into a new Array.
Synopsis
The function concatenates two Arrays into a new Array.
The shape of both arrays must match except for the last dimension.
The shape of the resulting array is equal to that of the input
arrays with its last dimension as the sum of both last dimensions.
An exception ArrayConformanceError is thrown when the shapes
do not match.
Motivation
The table system needed this function.
Example
Vector<Int> vector1(5);
Vector<Int> vector2(10);
indgen (vector1); // fill with values 0..4
indgen (vector2); // fill with values 0..9
Vector<Int> result = concatenateVector (vector1, vector2);
The example above results in a vector with length 15 and values
0,1,2,3,4,0,1,2,3,4,5,6,7,8,9.
It can also be used with matrices or arrays with higher dimensionality
as long as all dimensions but the last one have equal length.
Matrix<Int> matrix1 (3,4);
Matrix<Int> matrix2 (3,5);
Matrix<Int> matrix3 (4,4);
// Concatenation of matrix1 and matrix 2 will succeed and result
// in a 3x9 matrix.
Matrix<Int> matrixConc = concatenateArray (matrix1, matrix2);
if (matrixConc.shape() != IPosition(2,3,9)) {
cout << "Error in shape of concatenated matrices" << endl;
}
// Concatenation of matrix1 and matrix3 will fail, because the
// first dimensions have a different length (3 vs. 4).
try {
concatenateArray (matrix1, matrix2);
} catch (ArrayConformanceError x) {
cout << x.getMesg() << endl;
}
Example
Member Description
Interface
- Array<T> reorderArray (const Array<T>& array, const IPosition& newAxisOrder, Bool alwaysCopy = True)
Review Status
- Reviewed By:
- UNKNOWN
- Date Reviewed:
- before2004/08/25
- Programs:
- Tests:
Synopsis
This function makes it possible to reorder the axes of an array.
The resulting array is a copy of the input array with its data
moved around according to the new array order.
If the order does not change, a copy is returned if the
alwaysCopy is true. Otherwise a reference of the
input array is returned.
The newAxisOrder defines the new axes order.
Its length can be less than the dimensionality of the input array.
It is appended with the non-specified axes in their natural order.
newAxisOrder(i) gives the axis in the original array
which will now get axis i.
Example
Array<Int> result = reorderArray (someArray, IPosition(2,1,3));
Say that someArray is a 4D array with shape [3,4,5,6].
The non-specified axes get appended to the axis order
specification [1,3] resulting in [1,3,0,2].
This means that axis 1 gets axis 0, axis 3 gets axis 1, axis 0 gets
axis 2, and axis 2 gets axis 3.
Thus the resulting shape is [4,6,3,5] and the data are moved accordingly.
Motivation
This function was needed for an efficient implementation of the
functions partialMedians and partialFractiles.
Member Description
Array<T> reorderArray (const Array<T>& array, const IPosition& newAxisOrder, Bool alwaysCopy = True)
Interface
- uInt reorderArrayHelper (IPosition& newShape, IPosition& incr, const IPosition& shape, const IPosition& newAxisOrder)
Review Status
- Reviewed By:
- UNKNOWN
- Date Reviewed:
- before2004/08/25
- Programs:
- Tests:
Synopsis
This is a specialized helper function for function reorderArray.
It determines the shape of the resulting array and calculates the
result increments when iterating linearly through the source array.
It returns the number of the first non-reordered axes.
Motivation
Split off common non-templated code.
Member Description