- Tcl/Tk 8.5 Programming Cookbook
- Copyright
- Credits
- About the Author
- Acknowledgment
- About the Reviewers
- www.PacktPub.com
- Preface
- 1. The Tcl Shell
- 2. Using the Building Blocks Control Constructs
- 3. Error Handling
- 4. Handling String Expressions
- Introduction
- Appending to a string
- Formatting a string
- Matching a regular expression within a string
- Performing character substitution on a string
- Parsing a string using conversion specifiers
- Determining the length of a string
- Comparing strings
- Comparing a string of characters
- Locating the first instance of a character
- Locating the index of a character
- Determining the class of a string
- Locating the last instance of a string
- Determining the size of a string
- Replacing values within a string
- Locating a pattern within a string
- Returning a range of characters from a string
- Creating a string of repeated characters
- Replacing ranges of characters contained within a string
- Creating a reverse string
- Converting a string to lowercase
- Converting a string to title
- Converting a string to uppercase
- Trimming a string
- Trimming leading whitespace
- Trimming trailing whitespace
- Locating the word end
- Locating the word start
- Performing variable substitution
- 5. Expanding String Functionality Using Lists
- Introduction
- Creating a list
- Joining two lists
- Joining list elements
- Appending list elements
- Assigning list elements to variables
- Retrieving an element from a list
- Inserting elements into a list
- Determining the number of elements
- Getting a list element
- Repeating elements
- Replacing elements
- Reversing elements
- Searching a list
- Editing a list
- Sorting a list
- Splitting a string into a list
- 6. The Tcl Dictionary
- Introduction
- 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
- Creating a blank dictionary structure
- Updating variables from a dictionary
- Determining the size of a dictionary
- Getting all records
- Assigning values
- 7. File Operations
- 8. Tk GUI Programming with Tcl/Tk
- 9. Configuring and Controlling Tk Widgets
- 10. Geometry Management
- 11. Using Tcl Built-in Dialog Windows
- 12. Creating and Managing Menus
- 13. Creating the Address Book Application
To provide more flexibility to our programs, it will be necessary to create and maintain your lists dynamically. As this will result in a list of indeterminate size, we need a means to determine the number of elements in a list. To accomplish this, Tcl provides the llength command. The syntax is as follows:
llength list
In the following example, we will pass a list to the llength command to determine the number of elements the list contains. Return values from the commands are provided for clarity. Enter the following command:
% llength {John Mary { Bill Tom }}
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