High-speed Lookups with Clusters: FINDROW(), FINDVALUE(), and FINDVALUE$()

The FINDROW() High-Speed Data Lookup Function

Clusters provide a powerful way to create high-speed lookup tables, ideal for tasks such as translation. Each field within a cluster can serve as a searchable key, and lookups are performed using the findrow() function.

findrow() supports all data types, allows duplicate keys, and permits key values to change over time. Missing or unset values are handled naturally using empty strings or zero—without special cases, performance penalties, or data loss from duplicate empty keys.

findrow() is a highly optimized function that uses hashing to perform lookups in O(1) constant time, enabling over 10 million searches per second on a modern PC, regardless of the number of rows, subject to available RAM. This makes findrow() ideal for workloads requiring fast, deterministic data access.

Note: Hashing structures are built on demand the first time a field is searched, and are maintained automatically thereafter. Each hashed field sustains roughly 5 million value additions or changes per second on a modern PC.

Given a cluster name, a cluster field to search, and a value to match, findrow() returns the first row where the key is found and makes that row current, or returns 0 if the key is not found.

To handle duplicate keys, findrow() supports an optional parameter that selects the Nth occurrence of a matching key.

All cluster fields, regardless of data type, are searchable
All key values are mutable
Duplicate keys are fully supported
All key lookups execute in O(1) constant time

By default, all searches are case-insensitive. Set the optional fourth parameter to TRUE if you want a case-sensitive search.

Because all cluster fields are keys, bi-directional lookups are easy to do. In our example we will translate from English to German and German to English.

To define a cluster, use the cluster statement followed by the name of the cluster. In our example, we are calling our cluster trans. Our trans cluster has two fields: english$ and german$. To reference them we use trans->english$ and trans->german$.

cluster trans: english$, german$

The code below uses the trans cluster to translate from English to German and German to English.

// simple translation dictionary cluster trans: english$, german$ add cluster trans: english$ = 'apple', german$ = 'der Apfel' add cluster trans: english$ = 'banana', german$ = 'die Banane' word$ = a$ do // First, try translating English to German row = findrow(trans->english$, word$) if row > 0 then print word$;' >> '; trans->german$ exit do end if // Not found as English, try German row = findrow(trans->german$, word$) if row > 0 then print word$;' >> '; trans->english$ exit do end if print 'No translation for '; word$ end do

Program Explanation:

1. Cluster Definition:

A cluster named trans is defined to store English words and their corresponding German translations. The cluster has two fields: english$ for English words and german$ for German words.

2. Adding Data:

The program adds entries to the trans cluster:

The English word 'apple' is paired with the German word 'der Apfel'.
The English word 'banana' is paired with the German word 'die Banane'.

3. User Input Assignment:

The variable word$ is assigned the value of a$, which is assumed to be a word entered by the user that they want to translate.

4. Searching for English Word:

The program searches the trans cluster for a row where the english$ field matches word$ (the word entered by the user). The row number is stored in the variable row.

5. English to German Translation:

If the word is found (row > 0), the program prints the English word followed by its German translation, using ' >> ' as the separator. The loop then exits since the translation has been found.

6. Searching for German Word:

If the word wasn't found in the English field, the program then searches the trans cluster for a row where the german$ field matches word$.

7. German to English Translation:

If the word is found in the German field (row > 0), the program prints the German word followed by its English translation, again using ' >> ' as the separator. The loop then exits since the translation has been found.

8. No Translation Found:

If the word is not found in either the English or German fields, the program prints a message indicating that there is no translation available for the word entered by the user.

Simplified Lookups with FINDVALUE() and FINDVALUE$()

The findvalue() and findvalue$() functions look up a row in a cluster by searching one field, then return a specified value when that row is found.

The returned value may come from the matched row, such as emp->name$ or emp->salary, or it may be any compatible expression, variable, or constant.

// Return data from the matched row name$ = findvalue$(emp->id, myid, emp->name$, "not found") // Return a constant when the row exists message$ = findvalue$(emp->id, myid, "found it", "not found")

As a side effect, _integer is set to the matching row number. If no matching row is found, _integer is set to 0.

The current cluster row is not changed by findvalue() or findvalue$(). This means they can be safely used inside cluster iteration loops without disturbing the loop's current row.

Problem: Business programs often need to find a row by one field, then read another field from that same row. Without a helper function, this requires a findrow(), a test for zero, and a separate field reference.

Solution: findvalue() and findvalue$() combine the lookup, the not-found test, and the returned value into one expression.

Efficiency: The function uses Sheerpower's cluster lookup model directly. Any cluster field can become a key when searched, so no separate key/value table or declaration is needed.

Takeaway: Use findvalue() or findvalue$() when the real intent is: find this row, return this value, otherwise use this explicit fallback.

FINDVALUE() — Return a Numeric Value from a Matched Row

Syntax

num = findvalue(search_field, search_value, found_result, not_found_result [, nth] [, case_sensitive])

Description

findvalue() searches a cluster field for a matching value. If a matching row is found, Sheerpower positions the cluster to that row, evaluates found_result, and returns the resulting numeric value.

If no matching row is found, findvalue() returns not_found_result.

Use findvalue() when the value being returned is numeric.

Arguments

search_field
A cluster field designator that identifies the field to search. This is the same form accepted by findrow(), such as emp->id, emp->salary, or invoice->number.

search_value
The value to match in search_field. The search value may be numeric or string, depending on the field being searched.

found_result
The numeric value to return when a matching row is found. This may be a numeric field designator, a numeric variable, or a numeric constant.

If found_result is a cluster field designator, it is evaluated after the cluster has been positioned to the matched row.

not_found_result
The numeric value to return when no matching row is found.

This argument is required. There is no silent default.

nth
Optional. Selects which matching row to use when duplicate matches exist. 1 means the first match and is the default.

case_sensitive
Optional. Controls whether string searches are case-sensitive. When this argument is used, the nth argument must also be supplied.

Returns

findvalue() returns a numeric REAL value. Both found_result and not_found_result must be numeric.

Examples

// Find an employee by name and return the employee's salary salary = findvalue(emp->name$, "Bob", emp->salary, 0)

// Return 1 if the customer exists, otherwise return 0 exists? = findvalue(customer->id, id, true, false)

FINDVALUE$() — Return a String Value from a Matched Row

Syntax

text$ = findvalue$(search_field, search_value, found_result, not_found_result [, nth] [, case_sensitive])

Description

findvalue$() searches a cluster field for a matching value. If a matching row is found, Sheerpower positions the cluster to that row, evaluates found_result, and returns the resulting string value.

If no matching row is found, findvalue$() returns not_found_result.

Use findvalue$() when the value being returned is a string.

Arguments

search_field
A cluster field designator that identifies the field to search. This may be a string field, such as emp->name$, or a numeric field, such as emp->id.

search_value
The value to match in search_field. The search value is not determined by the $ on findvalue$(). The $ controls the return type, not the search type.

found_result
The string value to return when a matching row is found. This may be a string field designator, a string variable, or a string constant.

If found_result is a cluster field designator, it is evaluated after the cluster has been positioned to the matched row.

not_found_result
The string value to return when no matching row is found.

This argument is required. There is no silent default.

nth
Optional. Selects which matching row to use when duplicate matches exist. 1 means the first match and is the default.

case_sensitive
Optional. Controls whether string searches are case-sensitive. When this argument is used, the nth argument must also be supplied.

Returns

findvalue$() returns a string value. Both found_result and not_found_result must be strings.

Examples

// Search a numeric field and return a string field label$ = findvalue$(emp->id, 1234, emp->label$, "?")

// Find an employee by ID and return the employee's name name$ = findvalue$(emp->id, 1234, emp->name$, "[unknown]")

// Return the SKU from the third matching order line sku$ = findvalue$(line->order_id$, ord$, line->sku$, "", 3)

The Found Result Is Evaluated at the Matched Row

The most important rule is that found_result is evaluated at the matched row.

Sheerpower finds the matching row, positions the cluster to that row, evaluates found_result, and then restores the original row position. After the call, the cluster's current row is exactly what it was before the call; only _integer reflects the matched row number.

salary = findvalue(emp->name$, "Bob", emp->salary, 0)

This returns Bob's salary, not the salary from the row that happened to be current before the call.

This is what makes findvalue() more than a simple existence test. It is a lookup-and-return operation.

The Not-Found Result Is Required

The not_found_result argument is required for both findvalue() and findvalue$().

This forces every call site to make the not-found behavior visible. There is no hidden default and no silent assumption.

Use a fallback value when absence is ordinary.
Use 0 or "" when absence and empty mean the same thing.

// Ordinary fallback name$ = findvalue$(emp->id, id, emp->name$, "[unknown]") // Empty string is intentional sku$ = findvalue$(line->order_id$, ord$, line->sku$, "")

Simplifying the FINDROW() Pattern

A traditional lookup with findrow() looks like this:

row = findrow(emp->id, id) if row > 0 then salary = emp->salary // found the employee else salary = 0 // did not find the employee end if

With findvalue(), the same intent becomes one expression:

salary = findvalue(emp->id, id, emp->salary, 0)

The shorter form is not just more compact. It removes the row-number bookkeeping and says directly what the program means.

Problem: Repeated findrow() code makes the developer write mechanical lookup steps instead of the business intent.

Solution: findvalue() and findvalue$() express the lookup and returned value in one readable expression.

Efficiency: Because Sheerpower clusters can search on any field, this works without extra lookup tables, declarations, or special key/value conventions.

Takeaway: When you want data from the matched row, use findvalue() or findvalue$() instead of manually finding the row and testing it.

Summary

findvalue() returns a numeric value from a matched row. findvalue$() returns a string value from a matched row.

The search field may be numeric or string. The $ suffix on findvalue$() describes the returned value, not the searched value.

The found result is evaluated after the matching row is found and the cluster is positioned to that row.

The not-found result is required, so every lookup clearly states what happens when the row is absent.

(Show/Hide Sheerpower FINDVALUE() Takeaways)

Summary:

findrow() is a core language feature for fast, deterministic data access, not a helper routine or external index.
A single cluster can support bi-directional lookups across multiple fields, enabling flexible data models without duplicating or restructuring data.
All cluster fields are first-class keys, allowing lookups on any attribute with no additional setup or configuration.
Lookups execute in O(1) constant time regardless of cluster size, preserving predictable performance as data grows.
Duplicate, mutable, and empty keys are handled naturally, eliminating special-case logic and preventing data loss or indexing errors.
By integrating hashing and lookup semantics at the language level, findrow() removes an entire class of application-level indexing code while remaining simple to read and reason about.

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