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In all versions of Python, boolean operators treat zero values or empty values such as "", 0, None, 0.0, [], and {} as false, while in general treating non-empty, non-zero values as true. The boolean values True and False were added to the language in Python 2.2.1 as constants (subclassed from 1 and 0 ) and were changed to be full blown ...
Reference types support the notion of subtyping, whereby all values of a given reference type are automatically values of a different reference type. Value types do not support subtyping, but may support other forms of implicit type conversion , e.g. automatically converting an integer to a floating-point number if needed.
The same technique can be used to map two-letter country codes like "us" or "za" to country names (26 2 = 676 table entries), 5-digit ZIP codes like 13083 to city names (100 000 entries), etc. Invalid data values (such as the country code "xx" or the ZIP code 00000) may be left undefined in the table or mapped to some appropriate "null" value.
The similarity of two strings and is determined by this formula: twice the number of matching characters divided by the total number of characters of both strings. The matching characters are defined as some longest common substring [3] plus recursively the number of matching characters in the non-matching regions on both sides of the longest common substring: [2] [4]
The symbol table must have some means of differentiating references to the different "p"s. A common data structure used to implement symbol tables is the hash table. The time for searching in hash tables is independent of the number of elements stored in the table, so it is efficient for a large number of elements.
These special sequences are character references. Character references that are based on the referenced character's UCS or Unicode code point are called numeric character references. In HTML 4 and in all versions of XHTML and XML, the code point can be expressed either as a decimal (base 10) number or as a hexadecimal (base 16) number. The ...
The number 0, the strings "0" and "", the empty list (), and the special value undef evaluate to false. [8] All else evaluates to true. Lua has a Boolean data type, but non-Boolean values can also behave as Booleans. The non-value nil evaluates to false, whereas every other data type
In a statement such as while ((ch = getchar ())!= EOF) {…}, the return value of a function is used to control a loop while assigning that same value to a variable. In other programming languages, Scheme for example, the return value of an assignment is undefined and such idioms are invalid.