Common Programming Operations

Object Comparison

Python

# Compares values for equality
# For example, check if two numbers or strings are the same
a == b
 
# Compares identity
# Whether two variables point to the same object in memory
a is b

SQL

-- Compares a value or column to another value.
-- If either side of the comparison is `NULL`, the result is `NULL` (not `TRUE`).
SELECT * 
FROM employees 
WHERE salary = 5000;
 
-- Checks for `NULL` or `NOT NULL` values explicitly.
SELECT * FROM employees WHERE bonus IS NULL;

Defining Custom Comparison Logic

Java

class Node implements Comparable<Node> {
    public int freq;
   
    @Override
    public int compareTo(Node other) {
        return Integer.compare(other.freq, this.freq);
    }
}

The comparator logic above implements a descending order. To achieve ascending order, swap other.freq and this.freq
For more details, refer to Java Comparison

Python

class Node:
    def __init__(self, val, freq):
        self.freq = freq
    
    def __lt__(self, other):
        return other.freq < self.freq

The comparator logic above implements a descending order. To achieve ascending order, swap other.freq and self.freq

C++

class Node {
public:
    int freq;
 
	Node(int freq) {
		this->freq = freq;
	}
 
	bool operator<(const Node& other) {
		return other.freq > this->freq;
	}
}

The comparator logic above implements a descending order. To achieve ascending order, swap other.freq and self->freq