LEFTB Function (Gnumeric)

• Introduced: Introduced in Gnumeric 1.9.10 release notes.
• Supported in: Registered in Gnumeric 1.12.62; no retirement is established.
• Last functioning version: Selected calculations are verified in 1.12.57. The newest functioning release is unverified; source registration in 1.12.62 does not establish newer runtime results.
• Scope: Desktop Gnumeric with its String Functions plugin. English comma-separated formulas are shown.
• Checked: October 14, 2026. Tables use 1.12.57 ssconvert under C.UTF-8; 1.12.62 was source-inspected only.

LEFTB returns a prefix containing complete UTF-8 characters, with at most the requested number of bytes. If the byte budget ends inside a character, that character is omitted rather than split. It does not pad the result to the requested length. Versioned function help.

=LEFTB(text[,num_bytes])

• text: Required source text.
• num_bytes: Optional maximum byte count; the default is 1. Nonnegative fractional counts are truncated in the tested cases. Negative counts give #VALUE!.

Brackets indicate optional arguments; do not type them. Current worksheet implementation.

The native column records recalculated CSV field content. Quotes delimit readable text; "" means an empty field expected to be text from the callback. They do not certify the exported cell type. The independent column checks the stated character mapping, UTF-8 byte operation or decimal conversion.

For a UTF-8 field capped at three bytes, =LEFTB("Lévy",3) returns Lé. Reducing the budget to two bytes returns only L, because the two-byte é would cross the limit. Put the original in A2 and the budget in B2, then use =LEFTB(A2,B2). Keep the unshortened value when truncation could create duplicate identifiers.

The saved =LEFTB("Lévy",3)&RIGHTB("Lévy",2) reconstructs Lévy, because the split falls exactly between complete characters. This is not true for every pair of byte budgets: a split through the two-byte é would omit it from one or both pieces.

For A😀B, the emoji occupies bytes 2–5. A four-byte prefix budget returns only A; a five-byte budget returns A😀. This illustrates why a result may be substantially shorter than the requested maximum.

The default one-byte budget returns empty text for é, rather than one accented character. Use LEFT when the requirement is a character count. Zero bytes returns empty text; an oversized budget returns the full source. The selected 2.9-byte case behaves as two bytes.

F2 is Lévy and F5 is genuinely blank. These source and native checks concern complete UTF-8 code points; they do not promise preservation of a whole grapheme cluster made from several code points, such as a base letter followed by a combining accent.

The source snapshots and native results below were retained from October 14, 2026. The recovered guide was checked against those saved records on October 15; neither the application nor a newer release was executed again.

• Current worksheet callback
• Tested-version worksheet callback

The complete LEFTB callback is byte-identical between the two inspected releases. Both stale and uncached SUM controls recalculated correctly. Saved native XML retains the function identities. No GUI result display, other locale, native output-type certification or newer-release execution is claimed.

LEFT, LEN, RIGHT.