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Other conventions are less common: Common Lisp and Macsyma/Maxima use Basic-like operators for numerical values, except for inequality, which is /= in Common Lisp and # in Macsyma/Maxima. Common Lisp has multiple other sets of equality and relational operators serving different purposes, including eq, eql, equal, equalp, and string=. [6]
The topmost value is evaluated as a Boolean and, if true, the second topmost value is pushed back on the stack. IFTE allows a third "else" value that will be pushed back on the stack if the Boolean is false. The following example uses the IFT function to pop an object from the bottom of the stack and, if it is equal to 1, replaces it with "One":
In information theory, the Hamming distance between two strings or vectors of equal length is the number of positions at which the corresponding symbols are different. In other words, it measures the minimum number of substitutions required to change one string into the other, or equivalently, the minimum number of errors that could have transformed one string into the other.
In computer science, a Boolean expression is an expression used in programming languages that produces a Boolean value when evaluated. A Boolean value is either true or false.A Boolean expression may be composed of a combination of the Boolean constants True/False or Yes/No, Boolean-typed variables, Boolean-valued operators, and Boolean-valued functions.
If n is greater than the length of the string then most implementations return the whole string (exceptions exist – see code examples). Note that for variable-length encodings such as UTF-8 , UTF-16 or Shift-JIS , it can be necessary to remove string positions at the end, in order to avoid invalid strings.
Python's is operator may be used to compare object identities (comparison by reference), and comparisons may be chained—for example, a <= b <= c. Python uses and, or, and not as Boolean operators. Python has a type of expression named a list comprehension, and a more general expression named a generator expression. [78]
For example, += and -= are often called plus equal(s) and minus equal(s), instead of the more verbose "assignment by addition" and "assignment by subtraction". The binding of operators in C and C++ is specified (in the corresponding Standards) by a factored language grammar, rather than a precedence table. This creates some subtle conflicts.
Python supports a wide variety of string operations. Strings in Python are immutable, so a string operation such as a substitution of characters, that in other programming languages might alter the string in place, returns a new string in Python. Performance considerations sometimes push for using special techniques in programs that modify ...