ISNA in Calligra Sheets: Identify Missing-Value Errors

ISNA returns TRUE only for a genuine N/A error, not for arbitrary errors or text that spells "#N/A". The source checks args[0].isError() and equality with Calligra’s internally constructed N/A error message. [E1–E3]

A failed lookup or missing laboratory measurement should often be reviewed differently from invalid arithmetic. ISNA lets an audit report explicitly recognize the missing-value category without flagging all other errors as missing records. Keep the original value and source row visible; the predicate classifies but does not supply the absent value. [E1–E4]

=ISNA(x)

One required parameter x (XML type Any, argument 1), Boolean return type. No extra parameters, optional arguments or defaults are declared. The release registry lists ISNA around line 90, and the pinned callback (lines 358–362) returns isError() && errorMessage()==errorNA().errorMessage(). The error constructor NA() is documented and registered as zero-argument near lines 113–115/407–410. [E1–E3]

Build a controlled worksheet. In A2:A6, enter the following. In B2, enter =ISNA(A2) and fill through B6. [E1–E4]

Expected B2:B6: TRUE, FALSE, FALSE, FALSE, FALSE, contingent on normal argument evaluation of error-valued cells. The NA() and ISNA callbacks were examined directly; the actual installed worksheet evaluator and locale-specific error display have not been tested. [E1–E4]

Advanced example 1 — distinguish missing from calculation faults

In C2, enter and copy down:

=IF(ISNA(A2);"Missing data";IF(ISERROR(A2);"Other error";"Available"))

The predicted classifications for A2/A3/A4 are Missing data, Other error, Available. The last result means only that the source value is not an error, not that its business meaning is valid. Keep the input visible rather than overwriting it. [E1–E4]

Advanced example 2 — count missing rows without changing inputs

For the five test rows, first enter =ISNA(A2) in B2 and fill it through B6, then in an unused cell type:

=COUNTIF(B2:B6;TRUE)

The independently reasoned expected count is 1 (the A2 NA() record), assuming Calligra’s COUNTIF accepts Boolean TRUE criteria in this form. This composed formula is a secondary native-validation target, not an observed Calligra result; for the strictest repeatable test, count the TRUE values manually in the displayed audit column. [E1–E4]

Comparison matrix

The matrix captures the distinct source predicates. They are separate registered functions, not aliases; an N/A marker is still a real spreadsheet error. [E1–E4]

• The cell shows "#N/A" but ISNA is FALSE: it might be text rather than an N/A error. Use =NA() to create a controlled native error value. [E1–E3]
• =1/0 is FALSE under ISNA: division by zero is not the N/A category; ISERROR would flag it if delivered to the callback. [E1–E3]
• Missing values are actually empty cells: an untouched cell is not the same as an N/A error marker. Combine ISNA with ISBLANK in a separate audit if the business definition includes blanks. [E1–E4]
• A lookup yields unexpected error classes: do not assume a lookup always produces N/A. Examine the returned error category and its original input before applying replacement logic. [E1–E4]
• Formula propagates an error instead of Boolean: the registered implementation and manual describe the intended predicate, but full evaluation, import and type-coercion pathways remain pending native testing. [E3–E4]
• Locale settings: the display token for a missing-value error can vary; the source compares internal error messages rather than visible quoted labels in a cell. [E3]

Excel and LibreOffice Calc officially document ISNA(value) as detecting an N/A error, which matches Calligra’s intended category. The same docs distinguish it from ISERROR and ISERR. The function’s English name matches, but formula import, error creation, comparison strings and locale conventions still require workbook-specific confirmation after migration. [E1, E5]

Will ISNA return TRUE for a blank cell? No under the documented definition: blank and N/A are different categories; exact blank-reference evaluation in an installed Calligra binary was not observed. [E1, E4]

Does the text "#N/A" count? No. The function tests an internal error value rather than searching a text string. [E3]

How can I intentionally test ISNA? Use a control cell with =NA(), which Calligra registers as returning its N/A error value, and then apply =ISNA(A2) in a separate cell. Native output remains to be verified. [E1–E3]

Calligra’s English reference uses a leading = for worksheet entry and a semicolon between arguments when a function needs several inputs. This function has one required argument, so its own syntax has no separator. The IF examples use ;; if your localized Calligra input configuration differs, use Insert → Function to verify separator entry. A displayed Boolean label or error message may be localized; compare the actual value category rather than translating a displayed error string. [E1, E2]

The implementation examined is the Calligra 26.08.2 function module at pinned commit 72123cc643f6625351139e7df294544255a1056f, associated with the 2026-10-08 release. The stable KF6 English handbook is an official description, not a log of this binary running on Linux, Windows or another platform. Calligra’s current KDE application page advertises a Linux install route; package availability and optional downstream patches can change. No installed Calligra application was available for native verification. [E1–E3, E6]

Validation taxonomy: DOC means an official handbook/XML statement; SOURCE means code inspected at the pinned revision; CALC means an independent truth-table or arithmetic check; EXPECTED means a predicted worksheet result. None of the displayed answers in these guides is a NATIVE_OBSERVED result. Recheck type-coercion, error propagation and localized displays before production use. [E1–E4]

• [E1 — KDE DOC] Official English Calligra Sheets function handbook, Information section for this named function and NA; accessed 2026-10-12. Official syntax, category and meanings.
• [E2 — KDE VERSION-PINNED XML] Calligra information.xml at 72123cc643f6, the exact <Function> entry. One Any argument, Boolean result and no declared optional parameter/default for this function; accessed 2026-10-12.
• [E3 — KDE VERSION-PINNED SOURCE] Calligra information.cpp at 72123cc643f6; corresponding Function registration and callback. Implementation observed in source, not a native run; accessed 2026-10-12.
• [E4 — INDEPENDENT LOGIC] The explicit input-type/error-category truth table shown above. Results calculated from Boolean predicates and documented error categories; not executed in Calligra.
• [E5 — COMPATIBILITY DOCS] Microsoft Excel IS functions and LibreOffice Calc information functions, both official vendor documentation, accessed 2026-10-12. Cross-product names and high-level meaning, not proof of identical parser/locale/runtime handling.
• [E6 — OFFICIAL RELEASE] KDE’s Calligra Sheets release listing, version 26.08.2 — October 8, 2026; accessed 2026-10-12.