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Articles by Pythonista
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How to generate prime numbers using Python?
A prime number is the one that is not divisible by any other number except 1 and itself.In Python % modulo operator is available to test if a number is divisible by other. Assuming we have to find prime numbers between 1 to 100, each number (let us say x) in the range needs to be successively checked for divisibility by 2 to x-1. This is achieved by employing two nested loops.for x in range(1,101): for y in range(2,x): if x%y==0:break else: print (x,sep=' ', end=' ')Above code generates prime numbers between 1-1001 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
Read MoreHow do we convert a string to a set in Python?
Python’s standard library contains built-in function set() which converts an iterable to set. A set object doesn’t contain repeated items. So, if a string contains any character more than once, that character appears only once in the set object. Again, the characters may not appear in the same sequence as in the string as set() function has its own hashing mechanism>>> set("hello") {'l', 'h', 'o', 'e'}
Read MoreHow to insert a Python tuple in a PostgreSql database?
PostgreSql database is by default installed on port number 5432. Python interface to PostgreSql is provided by installing psycopg2 module. Assuming that test database and employee table with fname, sname, age, gender and salary fields is available.First establish connection and obtain cursor object by following statements in Python script.import psycopg2 conn = psycopg2.connect(database = "test", user = "postgres", password = "pass123", host = "localhost", port = "5432") cur = conn.cursor()Data to be inserted in employee table is stored in the form of tuple objectt1=('Mac', 'Mohan', 20, 'M', 2000)Next set up the insert query using this tuplesql="insert into employee values(%s, %s, ...
Read MoreC++ 'a.out' not recognised as a command
Having entered following command from linux terminal −$ g++ helloworld.cppThe a.out file should be created in the current working directory if the compilation is successful. Check if a.out is created.To execute enter following from command line −$ ./a.outIn most cases, output of your source program is displayed. However, as in your case, error message indicating a.out is not executable is appearing. See the properties of a.out and make it executable (if not already) by following command −$ chmod +x a.outYou may require sudo privilege for this. In all probability this should work. all the best
Read MorecompareTo() definition mistake?
The example works correctly. The compareTo() method is called by a string object and takes another string object as argument. The return value is integer and is difference in Unicode values of characters of respective strings when they are not equal. The value can be -ve, 0 or +ve.
Read MoreJava is also not pure object-oriented like c++
the main() method in Java code is itself inside a class. The static keyword lets the main() method which is the entry point of execution without making an object but you need to write a class. In C++, main() is outside the class and writing class it self is not mandatory. Hence, C++ is not a pure object oriented language bu Java is a completely object oriented language.
Read MoreHow to write string functions in Java?
1) take a string from the user and check contains atleast one digit or not:Extract character array from string using toCharArray() method. Run a for loop over each character in array and test if it is a digit by static method isDigit() of character classpublic static boolean chkdigit(String str) { char arr[]=str.toCharArray(); for (char ch:arr) { if (Character.isDigit(ch)) { return true; } } return false; }2.) take ...
Read MoreWhy there is not do...while loop in Python?
PEP 315 (Python Enhancement Proposal) to include do..while statement has been rejected because it doen't fit in the general format of indented block statement: indented block used by every other Python compound statement. In words of Guido Van Rossum - "Please reject the PEP. More variations along these lines won't make the language more elegant or easier to learn. They'd just save a few hasty folks some typing while making others who have to read/maintain their code wonder what it means".
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