Search results
Results From The WOW.Com Content Network
For one-dimensional arrays, this facility may be provided as an operation append(A,x) that increases the size of the array A by one and then sets the value of the last element to x. Other array types (such as Pascal strings) provide a concatenation operator, which can be used together with slicing to achieve that effect and more.
Function CRC32 Input: data: Bytes // Array of bytes Output: crc32: UInt32 // 32-bit unsigned CRC-32 value // Initialize CRC-32 to starting value crc32 ← 0xFFFFFFFF for each byte in data do nLookupIndex ← (crc32 xor byte) and 0xFF crc32 ← (crc32 shr 8) xor CRCTable[nLookupIndex] // CRCTable is an array of 256 32-bit constants
Some compiled languages such as Ada and Fortran, and some scripting languages such as IDL, MATLAB, and S-Lang, have native support for vectorized operations on arrays. For example, to perform an element by element sum of two arrays, a and b to produce a third c , it is only necessary to write
The empty string has several properties: |ε| = 0. Its string length is zero. ε ⋅ s = s ⋅ ε = s. The empty string is the identity element of the concatenation operation. The set of all strings forms a free monoid with respect to ⋅ and ε. ε R = ε. Reversal of the empty string produces the empty string, so the empty string is a palindrome.
String concatenation is an associative, but non-commutative operation. The empty string ε serves as the identity element; for any string s, εs = sε = s. Therefore, the set Σ * and the concatenation operation form a monoid, the free monoid generated by Σ.
If is a set of symbols or characters, then is the set of all strings over symbols in , including the empty string . The set V ∗ {\\displaystyle V^{*}} can also be described as the set containing the empty string and all finite-length strings that can be generated by concatenating arbitrary elements of V {\\displaystyle V} , allowing the use ...
In array languages, operations are generalized to apply to both scalars and arrays. Thus, a+b expresses the sum of two scalars if a and b are scalars, or the sum of two arrays if they are arrays. An array language simplifies programming but possibly at a cost known as the abstraction penalty.
In computer programming, array slicing is an operation that extracts a subset of elements from an array and packages them as another array, possibly in a different dimension from the original. Common examples of array slicing are extracting a substring from a string of characters, the " ell " in "h ell o", extracting a row or column from a two ...