Why Does `String.StartsWith()` Return True for Empty Strings?

Why String.StartsWith() Returns True for Empty Prefixes

The question arises as to why the C# method string.StartsWith returns true when invoked with an empty string as the prefix. Surprisingly, this behavior aligns with the logical notion of a string starting with the empty string.

According to the method's definition, a string starts with a prefix if the first prefix.Length characters of the string match those of the prefix. In the case of an empty prefix, this means that the first zero characters of the string must match zero characters. Since this condition is always met, string.StartsWith logically returns true for empty prefixes.

An alternative definition of "starts with" would be:

"A string starts with a prefix if the first prefix.Length characters of the string, when joined together, are equal to the prefix."

Using this definition, string.StartsWith would also return true for empty prefixes because an empty prefix can be joined with any number of characters to produce the empty string.

Therefore, the behavior of string.StartsWith in returning true for empty prefixes is both semantically and logically consistent.

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