Null Checker Function in M Language

Code Analysis

The provided code snippet is written in M Language, which is commonly used in Power Query. The function defined in the code is designed to check whether a given value is null.

Simplified Explanation

Breakdown of the Code

1. Function Declaration:

   • let: This keyword introduces a block of code in M Language.
   • checkNull = (value) =>: This defines a function named checkNull that accepts a single parameter, value.

2. Conditional Logic:

   • if value = null then true else false: This line checks if the value is equal to null.
     • if: Checks a condition.
     • then: Executes the subsequent expression if the condition is true.
     • else: Executes the subsequent expression if the condition is false.
     • If value is null, the function returns true; otherwise, it returns false.

3. Return Statement:

   • in checkNull: This indicates that checkNull is the final output of the let block. The function can now be called to check for null values.

Key Concepts

• Null Value: In programming, null represents the absence of a value or an object. It is important to distinguish null from other values (such as 0, '' (empty string), or false).

• Functions: The syntax used here denotes a lambda function, which is a concise way to write functions without formally defining them using a full function declaration structure.

• Conditional Statements: This code utilizes a conditional (if-then-else) construct, which allows the program to execute different branches based on whether the specified condition is true or false.

Additional Examples

Example 1: Extended Functionality

The following example extends the check functionality to handle different types of inputs.

let
    checkValue = (value) =>
        if value = null then 
            "Value is null" 
        else if value = "" then 
            "Value is an empty string" 
        else 
            "Value is present"
in
    checkValue

Example 2: Using the Function

To use the checkNull function, call it with different inputs.

let
    checkNull = (value) =>
        if value = null then true else false,
    
    result1 = checkNull(null),       // returns true
    result2 = checkNull(5),          // returns false
    result3 = checkNull("text")      // returns false
in
    [result1, result2, result3]

Conclusion

The provided snippet effectively demonstrates how to create a simple function to determine if a value is null in M Language. It makes use of basic conditional logic and function declarations, both of which are fundamental concepts in programming. For those seeking to deepen their understanding of such topics, exploring the resources available through the Enterprise DNA Platform can be beneficial.