To start a career in Machine Learning, you must have done a training program based on, Python Course or R Programming. Some math background LIKE in linear algebra, statistics, and calculus is recommended, so take classes on these topics, if possible. If you are a beginner and want to know more about Machine Learning, then check out this course by Intellipaat which will teach you ML from basics: Machine Learning Course
And if you are more into youtube tutorials then here is an awesome video tutorial by Intellipaat which will clear all your doubts regarding the same:
If you are NOVICE and want to start it as a hobby, competitions in data science are a great way of engaging for example from Kaggle. You can take up some online classes and later in your career if you want to learn about machine learning, I would recommend starting with a project: learn your way by trying to solve a problem that you have at heart. You can find help on the Internet and by attending Meetups.
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