LEFTB
Returns the leftmost characters of a text string based on a number of bytes. Each double-byte character (DBCS) counts as 2 bytes; single-byte characters count as 1.
LEFTB(text, [num_bytes])Arguments
textThe text from which to extract the leftmost characters.num_bytesThe number of bytes to extract (default 1). Must be ≥ 0.(optional)
=LEFTB("Excel",3)Returns the first 3 bytes
=LEFTB("日本語",2)1 double-byte character = 2 bytes
=LEFTB("AB日本",4)2 single-byte + 1 double-byte = 4 bytes
- •On systems without DBCS support, LEFTB behaves like LEFT
- •Use LEFT to extract by character count instead of byte count
- •Mainly used in East Asian Excel installations
- •Useful when truncating to byte-based field length limits
- •Using LEFTB when LEFT (character-based extraction) is actually what's needed - LEFTB counts bytes, so a num_bytes value that seems right by character count can cut a double-byte character in half
- •Assuming num_bytes always corresponds directly to a whole number of characters - with double-byte text, an odd num_bytes value can split a single character, producing a garbled or unexpected result
- •Forgetting that on systems without double-byte character set support, LEFTB simply behaves like LEFT, so testing on a Western-locale machine can hide bugs that only appear with East Asian text
LEFTExtracts by character count instead of byte count, the correct choice for text that doesn't need double-byte-aware handling.RIGHTBPerforms the same byte-based extraction as LEFTB but from the end of the string instead of the beginning.MIDBExtracts from any starting byte position, a more flexible version of the same byte-counting logic LEFTB uses.Why did LEFTB cut off part of a character instead of a clean substring?
num_bytes probably fell in the middle of a double-byte character - since each such character occupies 2 bytes, an odd byte count can split one in half, producing a garbled result.
Should I use LEFT or LEFTB?
Use LEFT for ordinary character-based extraction. Reach for LEFTB only when you specifically need byte-based counting, such as matching a legacy system's storage limits for East Asian text.
Does LEFTB work the same as LEFT on a system without double-byte language support?
Yes, in that case there's no distinction between characters and bytes, so LEFTB and LEFT return identical results.
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