Euphoria – Sequences ”; Previous Next A sequence is represented by a list of objects in brace brackets { }, separated by commas. A sequence can contain both atoms and other sequences. For example − {2, 3, 5, 7, 11, 13, 17, 19} {1, 2, {3, 3, 3}, 4, {5, {6}}} {{“Zara”, “Ayan”}, 52389, 97.25} {} — the 0-element sequence A single element of a sequence may be selected by giving the element number in square brackets. Element numbers start at 1. For example, if x contains {5, 7.2, 9, 0.5, 13} then x[2] is 7.2. Suppose x[2] contains {11,22,33}, Now if you ask for x[2] you get {11,22,33} and if you ask for x[2][3], you get the atom 33. Example #!/home/euphoria-4.0b2/bin/eui sequence x x = {1, 2, 3, 4} for a = 1 to length(x) do printf(1, “value of x[%d] = %dn”, {a, x[a]}) end for Here, length() is the built-in function which returns length of the sequence. The above example produces the following result − value of x[1] = 1 value of x[2] = 2 value of x[3] = 3 value of x[4] = 4 Character String A character string is just a sequence of characters. It may be entered in one of the two ways − (a) Using Double Quotes − “ABCDEFG” (b) Using Raw String Notation − — Using back-quotes `ABCDEFG` or — Using three double-quotes “””ABCDEFG””” You can try the following example to understand the concept − #!/home/euphoria-4.0b2/bin/eui sequence x x = “ABCD” for a = 1 to length(x) do printf(1, “value of x[%d] = %sn”, {a, x[a]}) end for This produces the following result − value of x[1] = A value of x[2] = B value of x[3] = C value of x[4] = D String Arrays An array of strings can be implemented using Sequences as follows − #!/home/euphoria-4.0b2/bin/eui sequence x = {“Hello”, “World”, “Euphoria”, “”, “Last One”} for a = 1 to length(x) do printf(1, “value of x[%d] = %sn”, {a, x[a]}) end for This produces the following result − value of x[1] = Hello value of x[2] = World value of x[3] = Euphoria value of x[4] = value of x[5] = Last One Euphoria Structures A structure can be implemented using Sequences as follows − #!/home/euphoria-4.0b2/bin/eui sequence employee = { {“John”,”Smith”}, 45000, 27, 185.5 } printf(1, “First Name = %s, Last Name = %sn”, {employee[1][1],employee[1][2]} ) This produces the following result − First Name = John, Last Name = Smith There are various operations which can be performed directly on sequences. Let us see them in detail − Urinary Operation When applied to a sequence, a unary operator is actually applied to each element in the sequence to yield a sequence of results of the same length. #!/home/euphoria-4.0b2/bin/eui sequence x x = -{1, 2, 3, 4} for a = 1 to length(x) do printf(1, “value of x[%d] = %dn”, {a, x[a]}) end for This produces the following result − value of x[1] = -1 value of x[2] = -2 value of x[3] = -3 value of x[4] = -4 Arithmetic Operations Almost all arithmetic operations can be performed on sequences as follows − #!/home/euphoria-4.0b2/bin/eui sequence x, y, a, b, c x = {1, 2, 3} y = {10, 20, 30} a = x + y puts(1, “Value of a = {“) for i = 1 to length(a) do printf(1, “%d,”, a[i]) end for puts(1, “}n”) b = x – y puts(1, “Value of b = {“) for i = 1 to length(a) do printf(1, “%d,”, b[i]) end for puts(1, “}n”) c = x * 3 puts(1, “Value of c = {“) for i = 1 to length(c) do printf(1, “%d,”, c[i]) end for puts(1, “}n”) This produces the following result − Value of a = {11,22,33,} Value of b = {-9,-18,-27,} Value of c = {3,6,9,} Command Line Options A user can pass command line options to a Euphoria script and it can be accessed as a sequence using command_line() function as follows − #!/home/euphoria-4.0b2/bin/eui sequence x x = command_line() printf(1, “Interpeter Name: %sn”, {x[1]} ) printf(1, “Script Name: %sn”, {x[2]} ) printf(1, “First Argument: %sn”, {x[3]}) printf(1, “Second Argument: %sn”, {x[4]}) Here printf() is Euphoria”s built-in function. Now if you run this script as follows − $eui test.ex “one” “two” This produces the following result − Interpeter Name: /home/euphoria-4.0b2/bin/eui Script Name: test.ex First Argument: one Second Argument: two
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