The following example is a sample Fortran array:
integer*4 arr(1:6, 4:7)
To evaluate the array, use the print command. For example:
(dbx) print arr(2,4)
The dbx print command enables you to evaluate part of a large array. Array evaluation includes:
You can slice an array, with or without striding. (The default stride value is 1, which means print each element.)
Array slicing is supported in the print, display, and watch commands for C, C++, and Fortran.
print array-expression [first-expression .. last-expression : stride-expression]
Expression that should evaluate to an array or pointer type.
First element to be printed. Defaults to 0.
Last element to be printed. Defaults to upper bound.
Length of the stride (the number of elements skipped is stride-expression-1). Defaults to 1.
The first expression, last expression, and stride expression are optional expressions that should evaluate to integers.
(dbx) print arr[2..4] arr[2..4] =  = 2  = 3  = 4 (dbx) print arr[..2] arr[0..2] =  = 0  = 1  = 2 (dbx) print arr[2..6:2] arr[2..6:2] =  = 2  = 4  = 6
print array-expression (first-expression : last-expression : stride-expression)
Expression that should evaluate to an array type.
First element in a range, also first element to be printed. Defaults to lower bound.
Last element in a range, but might not be the last element to be printed if stride is not equal to 1. Defaults to upper bound.
Length of the stride. Defaults to 1.
The first expression, last expression, and stride expression are optional expressions that should evaluate to integers. For an n-dimensional slice, separate the definition of each slice with a comma.
(dbx) print arr(2:6) arr(2:6) = (2) 2 (3) 3 (4) 4 (5) 5 (6) 6 (dbx) print arr(2:6:2) arr(2:6:2) = (2) 2 (4) 4 (6) 6
To specify rows and columns:
demo% f95 -g -silent ShoSli.f demo% dbx a.out Reading symbolic information for a.out (dbx) list 1,12 1 INTEGER*4 a(3,4), col, row 2 DO row = 1,3 3 DO col = 1,4 4 a(row,col) = (row*10) + col 5 END DO 6 END DO 7 DO row = 1, 3 8 WRITE(*,’(4I3)’) (a(row,col),col=1,4) 9 END DO 10 END (dbx) stop at 7 (1) stop at "ShoSli.f":7 (dbx) run Running: a.out stopped in MAIN at line 7 in file "ShoSli.f" 7 DO row = 1, 3
To print row 3:
(dbx) print a(3:3,1:4) ’ShoSli’MAIN’a(3:3, 1:4) = (3,1) 31 (3,2) 32 (3,3) 33 (3,4) 34 (dbx)
To print column 4:
(dbx) print a(1:3,4:4) ’ShoSli’MAIN’a(1:3, 1:4) = (1,4) 14 (2,4) 24 (3,4) 34 (dbx)
The following example is a two-dimensional, rectangular slice of a C++ array, with the default stride of 1 omitted.
This command prints a block of elements in a large array. Note that the command omits stride-expression, using the default stride value of 1.
As illustrated, the first two expressions (201:203) specify a slice in the first dimension of this two-dimensional array (the three-row column). The slice starts with row 201 and ends with 203. The second set of expressions, separated by a comma from the first, defines the slice for the second dimension. The slice begins with column 101 and ends with column 105.
The third expression in the array slicing syntax, stride-expression, specifies the length of the stride. The value of stride-expression specifies the elements to print. The default stride value is 1, meaning: evaluate all of the elements in the specified slices.
The following example is the same array used in the previous example of a slice. This time, the print command includes a stride of 2 for the slice in the second dimension.
print arr(201:203, 101:105:2)
As shown in the diagram, a stride of 2 prints every second element, skipping every other element.
For any expression you omit, print takes a default value equal to the declared size of the array. The following examples show how to use the shorthand syntax.
For a one-dimensional array, use the following commands:
Prints the entire array with default boundaries.
Prints the entire array with default boundaries and default stride of 1.
Prints the entire array with a stride of stride-expression.
For a two-dimensional array, the following command prints the entire array.
The following command prints every third element in the second dimension of a two-dimensional array:
print arr (:,::3)