Editing Lempel–Ziv–Welch (section)

===Encoding===
Buffer input characters in a sequence ω until ω + next character is not in the dictionary.  Emit the code for ω, and add ω + next character to the dictionary.  Start buffering again with the next character. (The string to be encoded is "TOBEORNOTTOBEORTOBEORNOT#".)

{| class="wikitable" style="text-align: right; margin-left: auto; margin-right: auto;"
|-
! scope="col" width="6em" rowspan="2" | Current Sequence
! scope="col" width="4em" rowspan="2" | Next Char
! colspan="2" | Output
! scope="col" width="7em" rowspan="2" colspan="2" | Extended Dictionary
! rowspan="2" | Comments
|-
! Code || Bits
|-
| style="text-align: center;" | NULL
| style="text-align: center;" | T || ||
| style="border-right: none;" |
| style="border-left: none;" | ||
|-
| style="text-align: center;" | T
| style="text-align: center;" | O
| 20 || {{mono|10100}}
| style="border-right: none;" | 27:
| style="border-left: none;" | TO
| style="text-align: left;" | 27 = first available code after 0 through 26
|-
| style="text-align: center;" | O
| style="text-align: center;" | B
| 15 || {{mono|01111}}
| style="border-right: none;" | 28:
| style="border-left: none;" | OB ||
|-
| style="text-align: center;" | B
| style="text-align: center;" | E
| 2 || {{mono|00010}}
| style="border-right: none;" | 29:
| style="border-left: none;" | BE ||
|-
| style="text-align: center;" | E
| style="text-align: center;" | O
| 5 || {{mono|00101}}
| style="border-right: none;" | 30:
| style="border-left: none;" | EO ||
|-
| style="text-align: center;" | O
| style="text-align: center;" | R
| 15 || {{mono|01111}}
| style="border-right: none;" | 31:
| style="border-left: none;" | OR ||
|-
| style="text-align: center;" | R
| style="text-align: center;" | N
| 18 || {{mono|10010}}
| style="border-right: none;" | 32:
| style="border-left: none;" | RN
| style="text-align: left;" | 32 requires 6 bits, so for next output use 6 bits
|-
| style="text-align: center;" | N
| style="text-align: center;" | O
| 14 || {{mono|001110}}
| style="border-right: none;" | 33:
| style="border-left: none;" | NO ||
|-
| style="text-align: center;" | O
| style="text-align: center;" | T
| 15 || {{mono|001111}}
| style="border-right: none;" | 34:
| style="border-left: none;" | OT ||
|-
| style="text-align: center;" | T
| style="text-align: center;" | T
| 20 || {{mono|010100}}
| style="border-right: none;" | 35:
| style="border-left: none;" | TT ||
|-
| style="text-align: center;" | TO
| style="text-align: center;" | B
| 27 || {{mono|011011}}
| style="border-right: none;" | 36:
| style="border-left: none;" | TOB ||
|-
| style="text-align: center;" | BE
| style="text-align: center;" | O
| 29 || {{mono|011101}}
| style="border-right: none;" | 37:
| style="border-left: none;" | BEO ||
|-
| style="text-align: center;" | OR
| style="text-align: center;" | T
| 31 || {{mono|011111}}
| style="border-right: none;" | 38:
| style="border-left: none;" | ORT ||
|-
| style="text-align: center;" | TOB
| style="text-align: center;" | E
| 36 || {{mono|100100}}
| style="border-right: none;" | 39:
| style="border-left: none;" | TOBE ||
|-
| style="text-align: center;" | EO
| style="text-align: center;" | R
| 30 || {{mono|011110}}
| style="border-right: none;" | 40:
| style="border-left: none;" | EOR ||
|-
| style="text-align: center;" | RN
| style="text-align: center;" | O
| 32 || {{mono|100000}}
| style="border-right: none;" | 41:
| style="border-left: none;" | RNO ||
|-
| style="text-align: center;" | OT
| style="text-align: center;" | #
| 34 || {{mono|100010}}
| style="border-right: none;" |
| style="border-left: none;" |
| style="text-align: left;" | # stops the algorithm; send the cur seq
|-
| || || 0 || {{mono|000000}}
| style="border-right: none;" |
| style="border-left: none;" |
| style="text-align: left;" | and the stop code
|-
|}

:Unencoded length = 25 symbols × 5 bits/symbol = 125 bits
:Encoded length = (6 codes × 5 bits/code) + (11 codes × 6 bits/code) = 96 bits.

Using LZW has saved 29 bits out of 125, reducing the message by more than 23%. If the message were longer, then the dictionary words would begin to represent longer and longer sections of text, sending repeated words very compactly.