Working with Chunks

Storing into Chunks

In addition to accessing a portion of a value, chunk expressions can also be used to store into a portion of a value, provided the thing being accessed is a container.

You can also store something before or after a chunk:

Storing into Chunk Ranges

When storing into chunk ranges, the entire range will be replaced:

Storing into Chunks with Patterns

You can use occurrence and match with patterns for storing into chunks much like other chunk types, including storing into ranges of matches in the source string.

For information about using patterns, see SenseTalk Pattern Language Basics.

Storing into Nonexistent Chunks

If you store something into a chunk that is beyond the end of the container you are storing into, SenseTalk does its best to accommodate you. The results are different for different types of chunks. For text items beyond the number of items in the container:

Here, the word saturn was put into the fifth text item of a value that previously had only 3 text items. To accommodate the request, two addtional commas were automatically inserted before the word saturn so that it would become the new fifth item. The actual character inserted matches the current setting of the itemDelimiter property.

When storing into list items beyond the end of a list, the results are similar:

For lines, the behavior is very similar to that for text items. But because the lineDelimiter can be a list of several possible delimiters, any one of which could indicate a new line, it can't be used to provide the inserted delimiter. Instead, a separate global property called the lineFiller provides the delimiter string (by default, Return) that is inserted as many times as needed to fill the text out to the requested line number.

For word chunks beyond the end of the text, a simple delimiter is not enough. Because a word delimiter can be any amount of whitespace, simply inserting more spaces won't add more words. So the wordFiller global property provides a placeholder "word" (by default, "?") to insert along with spaces to fill out the text to the desired number of words:

For character chunks, the characterFiller global property (by default, ".") provides text to be repeated as needed to fill the text out to the desired character position:

When a negative chunk number larger than the number of chunks is used, the result is similar to the above descriptions for all chunk types, but with fillers or delimiters added at the beginning of the value to achieve the expected result:

Related Global Properties

As described above, SenseTalk includes global properties to provide filler text for those cases when you use chunk expressions to add characters, lines, or words to chunks that expand them beyond their current limits. These three properteis, the characterFiller, the lineFiller, and the wordFiller, are described in detail on Local and Global Properties for Chunk Expressions.

Storing into Multiple Chunks

You can store into multiple chunks at once by supplying a list of chunk numbers:

You can store multiple values at once by supplying a list of values as well as of chunk numbers:

Deleting Chunks

Chunks of containers, besides being stored into, can also be deleted. This is done with the delete command (described in detail in Text and Data Manipulation):

Example:

Example:

Counting Chunks

To find out how many of a given chunk type are present in some value, use the number function:

Example:

Example:

Example:

Number Function

Behavior: The number function counts the number of characters, words, lines, text items, list items, keys, values, or bytes in a value. Use this function whenever you need to determine how many of a particular chunk type are present in a value. If the value is empty, the result will always be zero. In addition to the usual text chunks and bytes, when expression is an object or property list chunks can be "keys" or "values" to count the number of keys or values that are defined in the object.

Syntax:

Example:

Testing for Presence of a Chunk Value

You can find out whether a particular value is present as one of the chunks of another value using the is among or is not among operator.

Is Among Operator

Behavior: The is among operator tests whether a particular value is present among the characters, words, lines, text items, list items, keys, values, or bytes in a value. This will only return true if the target value is equal to one of the specified chunks. Contrast this with the is in or contains operators which will only test whether one text string is a substring of another (see the second example). In addition to the usual text chunks, when expression is an object or property list chunks can be "keys" or "values" to test whether targetValue is one of the keys or values of the object.

Syntax:

Example:

Example:

Example:

Example:

Determining Chunk Position of a Value

You can find the ordinal position of characters, words, lines, text items, and list items within a value (searches are case-insensitive unless “considering case” or “with case” is specified). The number 0 will be returned if the target expression is not found:

Syntax:

Example:

To find the word, line, or item number that contains a value (rather than one that is equal to the value), use the word containing instead of of:

Counting Occurrences of a Chunk Value

To count how many times a particular chunk value occurs within a source value, use the number of occurrences or number of instances function.

Syntax:

Example:

Example:

Example:

Example:

If a specific chunk type is not named, characters are assumed unless the source value is a list or an object, in which case list items or property values are assumed, respectively:

Example:

Example:

For case-sensitive comparisons, use “considering case” (or set the caseSensitive property to true).

Example:

As a special case, “among the characters of” can be used not only to count occurrences of a single character, but of a sequence of characters.

Example:

Iterating Over All Chunks in a Value

To do something with each of the chunks within a value, use the repeat with each form of the repeat command (which is also described in Script Structure and Control Flow).

Example:

Extracting a List of Chunks Using Each Expressions

Any expression of the form each chunkType of sourceValue will yield a list containing all of the chunks of that type (if chunkType is omitted, item will be assumed).

Syntax:

Example:

Example:

More interestingly, an each expression can be part of a larger expression. Within the larger expression, operators apply to each item of the list rather than to the list as a whole.

Example:

Example:

Example:

Parentheses limit the scope of the larger each expression, limiting the behavior to applying to the list as a whole rather than to each individual item.

Example:

An each expression can also include a where clause to select a subset of the items in the list. The word each can be used within the where clause to refer to each source item.

Example:

Example:

Related:

• Each Expressions

 

This topic was last updated on August 19, 2021, at 03:30:51 PM.

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