reverseChars

reverseChars is a function or method that returns a new string consisting of the characters of the input in reverse order. It is a common utility in string processing, used for tasks such as decoding, text transformation, or palindrome checks. The operation is distinct from reversing the order of words or delimiters, as it targets the sequence of characters themselves.

When reversing a string, implementations may operate on different character units. A simple approach reverses code units (such as UTF-16 code units in some languages), which can break characters that are represented by multiple units or by combining marks. A robust reverse typically handles Unicode by reversing code points or grapheme clusters, depending on the desired level of semantics. This distinction matters for multilingual text and emoji sequences.

Performance characteristics usually involve linear time and linear extra space to construct the reversed result. Some languages offer in-place reversal for mutable strings, reducing memory allocations but requiring careful handling of encoding boundaries. Edge cases include empty strings, null or undefined inputs (which some functions treat as an error or return an empty string), and characters composed of surrogate pairs or combining marks.

Examples:

- In Python, reverseChars = s[::-1] reverses by code points in practice for most cases.

- In JavaScript, reverseChars could be implemented as Array.from(s).reverse().join('').

- In Java, a typical approach uses a StringBuilder and its reverse method, though it may not preserve all Unicode grapheme boundaries.

See also: string reversal, Unicode normalization, grapheme clusters.

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