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Articles by Mohd Mohtashim
Page 10 of 19
CGI Environment Variables in Python
All the CGI programs have access to the following environment variables. These variables play an important role while writing any CGI program.Sr.No.Variable Name & Description1CONTENT_TYPEThe data type of the content. Used when the client is sending attached content to the server. For example, file upload.2CONTENT_LENGTHThe length of the query information. It is available only for POST requests.3HTTP_COOKIEReturns the set cookies in the form of key & value pair.4HTTP_USER_AGENTThe User-Agent request-header field contains information about the user agent originating the request. It is name of the web browser.5PATH_INFOThe path for the CGI script.6QUERY_STRINGThe URL-encoded information that is sent with GET method ...
Read MoreSpecial Syntax with Parentheses in Python
Sr.No.Example & Description1R(?#comment)Matches "R". All the rest is a comment2R(?i)ubyCase-insensitive while matching "uby"3R(?i:uby)Same as above4rub(?:y|le))Group only without creating \1 backreference
Read MoreRegular Expression Patterns in Python
Except for control characters, (+ ? . * ^ $ ( ) [ ] { } | \), all characters match themselves. You can escape a control character by preceding it with a backslash.Following table lists the regular expression syntax that is available in Python −Sr.No.Pattern & Description1^Matches beginning of line.2$Matches end of line.3.Matches any single character except newline. Using m option allows it to match newline as well.4[...]Matches any single character in brackets.5[^...]Matches any single character not in brackets6re*Matches 0 or more occurrences of preceding expression.7re+Matches 1 or more occurrence of preceding expression.8re?Matches 0 or 1 occurrence of preceding ...
Read MoreRegular Expression Modifiers in Python
Regular expression literals may include an optional modifier to control various aspects of matching. The modifiers are specified as an optional flag. You can provide multiple modifiers using exclusive OR (|), as shown previously and may be represented by one of these −Sr.No.Modifier & Description1re.IPerforms case-insensitive matching.2re.LInterprets words according to the current locale. This interpretation affects the alphabetic group (\w and \W), as well as word boundary behavior(\b and \B).3re.MMakes $ match the end of a line (not just the end of the string) and makes ^ match the start of any line (not just the start of the string).4re.SMakes ...
Read MoreBase Overloading Methods in Python
Following table lists some generic functionality that you can override in your own classes −Sr.No.Method, Description & Sample Call1__init__ ( self [,args...] )Constructor (with any optional arguments)Sample Call : obj = className(args)2__del__( self )Destructor, deletes an objectSample Call : del obj3__repr__( self )Evaluable string representationSample Call : repr(obj)4__str__( self )Printable string representationSample Call : str(obj)5__cmp__ ( self, x )Object comparisonSample Call : cmp(obj, x)
Read MoreCreating Classes in Python
The class statement creates a new class definition. The name of the class immediately follows the keyword class followed by a colon as follows −class ClassName: 'Optional class documentation string' class_suiteThe class has a documentation string, which can be accessed via ClassName.__doc__.The class_suite consists of all the component statements defining class members, data attributes and functions.ExampleFollowing is the example of a simple Python class −class Employee: 'Common base class for all employees' empCount = 0 def __init__(self, name, salary): self.name = name self.salary = salary Employee.empCount += 1 def displayCount(self): ...
Read MoreOOP Terminology in Python
Class − A user-defined prototype for an object that defines a set of attributes that characterize any object of the class. The attributes are data members (class variables and instance variables) and methods, accessed via dot notation.Class variable − A variable that is shared by all instances of a class. Class variables are defined within a class but outside any of the class's methods. Class variables are not used as frequently as instance variables are.Data member − A class variable or instance variable that holds data associated with a class and its objects.Function overloading − The assignment of more than ...
Read MoreBuilt-in Dictionary Functions & Methods in Python
Python includes the following dictionary functions −Sr.NoFunction with Description1cmp(dict1, dict2)Compares elements of both dict.2len(dict)Gives the total length of the dictionary. This would be equal to the number of items in the dictionary.3str(dict)Produces a printable string representation of a dictionary4type(variable)Returns the type of the passed variable. If passed variable is dictionary, then it would return a dictionary type.Python includes following dictionary methods −Sr.NoMethods with Description1dict.clear()Removes all elements of dictionary dict2dict.copy()Returns a shallow copy of dictionary dict3dict.fromkeys()Create a new dictionary with keys from seq and values set to value.4dict.get(key, default=None)For key key, returns value or default if key not in dictionary5dict.has_key(key)Returns true ...
Read MoreBuilt-in Tuple Functions in Python
Python includes the following tuple functions −Sr.NoFunction with Description1cmp(tuple1, tuple2)Compares elements of both tuples.2len(tuple)Gives the total length of the tuple.3max(tuple)Returns item from the tuple with max value.4min(tuple)Returns item from the tuple with min value.5tuple(seq)Converts a list into tuple.
Read MoreBasic Tuples Operations in Python
Tuples respond to the + and * operators much like strings; they mean concatenation and repetition here too, except that the result is a new tuple, not a string.In fact, tuples respond to all of the general sequence operations we used on strings in the prior chapter −Python ExpressionResultsDescriptionlen((1, 2, 3))3Length(1, 2, 3) + (4, 5, 6)(1, 2, 3, 4, 5, 6)Concatenation('Hi!',) * 4('Hi!', 'Hi!', 'Hi!', 'Hi!')Repetition3 in (1, 2, 3)TrueMembershipfor x in (1, 2, 3): print x,1 2 3Iteration
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