Creating dictionaries – inserting and updating
A dictionary is one kind of Python mapping. The built-in type dict
class provides a number of common features. There are some common variations on these features defined in the collections
module.
As we noted in the Choosing a data structure recipe at the beginning of the previous chapter, we'll use a dictionary when we have a key that we need to map to a given value. For example, we might want to map a single word to a long, complex definition of the word, or perhaps some value to a count of the number of times that value has occurred in a dataset.
A dictionary with keys and integer counts is very common. We'll look at a detailed recipe that shows how to initialize the dictionary and update the counter.
Getting ready
We'll look at an algorithm for locating the various stages in transaction processing. This relies on assigning a unique ID to each request and including that ID with each log record...