| substring | of another string |
| Syntax | A substring is one of:
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| Description | A substring selects a part of another string. In form (a) the substring starts at the left position and runs to the right position. In form (b), the substring is only a single character. Turing support substrings of char(n) values.
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| Example |
var word : string := "bring"
put word (2 .. 4) % Outputs rin
put word (3) % Outputs i
put word (2 .. *) % Outputs ring; the star (*) means
% the end of the string.
put word (* - 2 .. * - 1 ) % Outputs in
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| Details | The leftmost possible position in a string is numbered 1. The last position in a string can be written as an asterisk (*). For example, word (2 .. *) is equivalent to word (2 .. length(word)). Each of leftPosition, rightPosition, and charPosition must have one of these forms:
The exact rules for the allowed values of leftPosition and rightPosition are:
This specifically allows null substrings such as word (1, 0) in which rightPosition is 0 and word (6, 5) in which leftPosition is one more that length (stringReference). Note that substrings are not assignable. For example, if s is a string, the statement s (3) := "a" is illegal in Turing. Turing supports substrings of char(n) values. See char(n). If a substring of char(n) value t has two operands, as in t(2..77), the result type of this operation is a string. If the substring has one operand, as in t(7), this becomes, in effect, a subscript into an array of characters. The result is a reference to a char, which can be assigned to or passed to a var parameter.
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| See also | string, char, char(n), explicitStringConstant, explicitCharConstant, catenation and length.
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