Question

Write an application that reads a line of text, tokenizes the line using space characters as delimiters and outputs only those words beginning with the letter "b".

Short answer

To output words starting with 'b', read the text, tokenize it by spaces, filter tokens starting with 'b', and print them.

Step-by-step solution

Read the Text Line

Prompt the user to input a line of text and store this input into a variable.

Tokenize the Input Text

Using the split() method, divide the input text into tokens (words), by using space as the delimiter.

Filter Tokens Starting with 'b'

Iterate through the list of tokens and select only those that start with the letter 'b'. This can be checked using the startswith() method.

Output Words Beginning with 'b'

Print the list of words that begin with the letter 'b' to the user, or handle it as required by your application.

Key concepts

Text Tokenization

Understanding text tokenization is crucial when handling text data in Java. It refers to the process of breaking down a string of text into smaller, more manageable pieces, called tokens. These tokens usually represent words, phrases, or other meaningful elements in the text that can be further processed or analyzed.

For instance, when you receive a sentence such as 'Java is fun', tokenizing this sentence with space as a delimiter results in three tokens: 'Java', 'is', and 'fun'. This is often the first step in text analysis and natural language processing (NLP) tasks because it simplifies the complexity of handling entire sentences at once. Tokenization makes it easier to work with individual components and apply various operations such as searching, modification, or filtering based on specific criteria.

String Splitting

String splitting goes hand in hand with text tokenization. In Java, the split() method of the String class is used to divide a string into an array of substrings based on specified delimiters. For example, splitting a sentence using a space character as the delimiter will separate the words in the sentence.

Using the split() method, the input text 'I like Java programming' can be split into tokens like so:

• 'I'
• 'like'
• 'Java'
• 'programming'

Afterward, these tokens can be individually examined or manipulated. Splitting strings is a frequent operation in Java applications that process text, and being adept at string manipulation is an essential skill for developers.

Conditional Filtering

After tokenizing and splitting text into an array of strings, you may need to further narrow down the results based on certain conditions. This is where conditional filtering comes in. By applying filters, you can create a subset of tokens that match a particular criterion, such as starting with a specific letter or containing a certain substring.

In Java, one way to achieve this is by iterating over the array of tokens and using the startsWith() method to check if a token meets the condition. For the exercise, the condition is to select words that begin with the letter 'b'. By looping through the array and applying this filter, you create a new collection containing only the desired elements. It's a powerful technique that, when mastered, enables precise control over data selection and manipulation within an application.