Learning to code requires not merely understanding of syntax (which is what a book will give you), but hands-on experience and detailed feedback/reviews on your code.
Python for Finance with Intro to Data Science is a great resource to learn Python, in a finance and data-centric way, utilizing the latest approaches and tools.
quantnet.com
The following are testimonials by students who recently completed the "Python for finance with intro to data science" online course. If you have questions, ask here and they are more than willing to answer.
quantnet.com
Disclaimer: I am the originator of this course.