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JavaScript automatically allocates memory, while a variable is declared. Garbage collection finds memory no longer used by the application and releases it since it is of no use. Garbage collector uses algorithms like Mark-and-sweep algorithm, to find the memory no longer used.This algorithm is used to free memory when an object is unreachable. The garbage collector identifies the objects, which are reachable or unreachable. These unreachable objects get the treatment from the automatic garbage collector.The Reference-Counting Garbage Collection is also used for garbage collection in JavaScript. The object will get automatically garbage collected if there are no references to it. ... Read More
There are two ways available to access value associated with a key in a dictionary collection object. The dictionary class method get() takes key as argument and returns value. >>> d1 = {'name': 'Ravi', 'age': 23, 'marks': 56} >>> d1.get('age') 23 Another way is to use key inside square brackets in front of dictionary object >>> d1 = {'name': 'Ravi', 'age': 23, 'marks': 56} >>> d1['age'] 23
To enhance performance, try to keep JavaScript external. The separate code makes it easier for web browsers to cache. However, use inline scripts only when you’re making single page websites. Still, it's better to use external code i.e. external JavaScript. To place JavaScript in external file create an external JavaScript file with the extension .js. After creating, add it to the HTML file in the script tag. The src attribute is used to include that external JavaScript file. If you have more than one external JavaScript file, then add it to the same web page to increase the performance of ... Read More
Yes, a java program is first compiled into bytecode which JRE can understand. ByteCode is then interpreted by the JVM making it as interpreted language.
Narrowing refers to passing a higher size data type like int to a lower size data type like short. It may lead to data loss. Casting is required for narrowing conversion. Following program output will be 44. public class MyFirstJavaProgram { public static void main(String []args) { int a = 300; byte b = (byte)a; // narrowing System.out.println(b); } }
The ondragstart event triggers when dragging of an element begins.You can try to run the following code to learn how to implement ondragstart JavaScript event − Example Live Demo .drag { float: left; width: 100px; height: 35px; ... Read More
The C++11 features supported by Intel are available as an official guide in their docs. You can check these features out on https://software.intel.com/en-us/articles/c0x-features-supported-by-intel-c-compiler.
Presence of a certain file in the computer can be verified by two ways using Python code. One way is using isfile() function of os.path module. The function returns true if file at specified path exists, otherwise it returns false. >>> import os >>> os.path.isfile("d:\Package1\package1\fibo.py") True >>> os.path.isfile("d:/Package1/package1/fibo.py") True >>> os.path.isfile("d:onexisting.txt") Note that to use backslash in path, two backslashes have to be used to escape out of Python string. Other way is to catch IOError exception that is raised when open() function has string argument corresponding to non-existing file. try: fo = open("d:onexisting.txt", ... Read More
The built-in functions repr() and str() respectively call object.__repr__(self) and object.__str__(self) methods. First function computes official representation of the object, while second returns informal representation of the object. Result of both functions is same for integer object. >>> x = 1 >>> repr(x) '1' >>> str(x) '1' However, it is not the case for string object. >>> x = "Hello" >>> repr(x) "'Hello'" >>> str(x) 'Hello' Return value of repr() of a string object can be evaluated by eval() function and results in valid string object. However, result of str() can not be evaluated. ... Read More
If you want another code while working in the same code document, then use comments. Comment the previous code and add the alternative code to test it. After the testing completes, uncomment the previous code. In this way, you can test both the codes. While using comments follow the below rules to create valid comments − Any text between a // and the end of a line is treated as a comment and is ignored by JavaScript. Any text between the characters /* and */ is treated as a comment. This may span multiple lines. JavaScript also recognizes the ... Read More