A boolean array in computer programming is a sequence of values that can contain only the values of true or false. By definition, a boolean can only be true or false and cannot contain any other values in between. An array is a sequence of data types that occupy numerical locations in a linear memory space. While the actual implementation of a Boolean array is often left to the compiler or computer language libraries, it is most efficiently done using bits rather than whole bytes or words. There are several uses for a Boolean array, including checking property flags and aligning configurations with physical hardware interfaces.
Woman doing handstand with a computer
The idea of a Boolean array stems from the original methods used to store information in computers where very little memory was available. The first implementation of a Boolean array took the form of an array of bits. This used larger data types, such as bytes or long integers, to store information, setting the data type bits to true or false. In this way, a single eight-bit-long byte can contain eight different true or false values, saving space and allowing efficient bitwise operations.
As the size of computer memory has increased, the need to use bit arrays has decreased. While using bits offers the ability to switch bits and use logical operators that allow for incredibly fast processing, it also requires custom code to handle these types of operations. Using a standard array structure to store a sequence of bytes is a simpler solution, but requires much more memory during program execution. This can be seen by creating an array of 32 boolean values. With a bit array, the data will only take up four bytes of memory, but a Boolean array can take between 32 and 128 bytes, depending on the system implementation.
Some computer programming languages actually implement a bit array when using a boolean array type, although this is not common. A boolean array has the advantage of being very easy to read when viewing the source code. Comparisons and assignments are clearly presented, whereas with a bit array you must use the logical operators ‘and’, ‘or’ and ‘not’, which could create confusing code.
Despite the ease of use, one feature that cannot be used with a Boolean array is a bitmask. A bitmask is a single-byte or larger data type that contains a sequence of true and false values related to various conditions. In a single operation, multiple bits can be checked for their true or false status at once. With an array of boolean values based on integers, it would be necessary to perform the same operation with a loop.
