What is machine learning ?

Machine learning is the practice of programming computers to learn from data. The program will easily be able to determine if given are important or are “spam”. In machine learning, data referred to as called training sets .

For examples :-

Let’s assume that you'd like to write the filter program without using machine learning methods. In this case, you would have to carry out the following steps: ∙ In the beginning, you'd take a look at what spam e-mails looks like. You might select them for the words or phrases they use, like “debit card,” “free,” and so on, and also from patterns that are used in the sender’s name or in the body of the email . Second, you'd write an algorithm to detect the patterns that you've seen, and then the software would flag emails as spam if a certain number of those patterns are detected. ∙ Finally, you'd test the program, and then redo the first two steps again until the results are good enough.  

But in machine learning is following the best practice . the program will take care of things by itself .