Chapter 6. The Tcl Dictionary

In this chapter, we will cover the following topics:

• Creating a dictionary

• Appending to a dictionary

• Determining if a key exists

• Filtering a dictionary

• Searching a dictionary

• Getting a record

• Incrementing a value

• Getting the dictionary structure

• Getting a list of keys

• Appending to an existing record

• Merging two dictionaries

• Create a blank dictionary structure

• Updating variables from a dictionary

• Determining the size of a dictionary

• Getting all records

• Assigning values

Introduction

Strings hold textual data from a single character to a large text file. Lists allow us to store groups of strings and lists in an organized manner. But neither offers a simple method for relating data elements to a key value, in the manner of an array or database. If you need to organize multiple items under a single group, nothing beats a dictionary.

Dictionary allows storage of data with a key/value mapping methodology, with each key in the dictionary mapping to a single value. Dictionaries are...