Python Tutorial: Finding documents

Want to learn more? Take the full course at https://learn.datacamp.com/courses/introduction-to-using-mongodb-for-data-science-with-python at your own pace. More than a video, you'll learn hands-on coding & quickly apply skills to your daily work. --- In the last lesson, we learned about databases, collections, and documents. We also learned how data structures in MongoDB relate to those of JSON and Python. In this lesson, we will learn how to query a collection to find documents of interest. Here we have an example document in the laureates collection. Finding documents in MongoDB reminds me of the work of this particular laureate. The remarkable rays named after him are today called x-rays. To find documents satisfying some criteria, we express those criteria as a document. This filter document mirrors the structure of documents to match in the collection. Imagine a filter document as an x-ray image like the one on the right. This image is one of the first x-ray images ever recorded. Imagine you use it to filter by eye a collection of color photos of people's hands. You might keep ones with five fingers and a ring on the ring finger. Here's another way to think about filter documents. Hold a pair of pants up to a collection of mammals, one at a time. The pants fit a part of the structure of human beings, but not that of a walrus. Sorry, Wally. Filter documents can be small. For example, there are 48 laureate documents with a value for the field "gender" equal to "female". We can do the same for other fields, like country of death and city of birth. Also, we can merge criteria into a single filter document. This filter document will have the same form as matching documents. In this case, the filter matches Marie Curie. She discovered the element polonium, named after her native land. Poland was under Russian rule at the time. She hoped that naming an element after it would publicize its lack of independence. Many immigrants won Nobel Prizes, but in what pro