Data Commands
The commands in this section create and modify data structures, mostly lists.
ASCII
Also: UNICODE
Converts a character into its Unicode value; one input.
Syntax
UNICODE character
ASCII character
Description
UNICODE reports the Unicode value of its input. The Unicode standard is a standard code for representing numbers, letters and symbols. If its input is a word, UNICODE reports the UNICODE value of the first character in the word. UNICODE reports an integer value. The input must contain at least one character. The character can be a letter, number or special character. To output the character corresponding to an UNICODE code input, use CHAR.
The alias ASCII is maintained for backward compatibility.
Examples
UNICODE “中 Result: 20013
BUTFIRST
Also: BF
Reports all but the first element of its input; one input.
Syntax
BUTFIRST word
BUTFIRST list
Description
BUTFIRST reports all but the first element of its input. If its input is a list, BUTFIRST reports a list containing all but the first element. If its input is a word or number, BUTFIRST reports all the characters of the word or number except the first character. See also BUTMEMBER, BUTLAST, FIRST, and LAST.
Examples
BUTFIRST [MARY HAD A LITTLE LAMB] Result: [HAD A LITTLE LAMB] BUTFIRST “WHEAT Result: HEAT BUTFIRST [WHEAT] Result: [] BUTFIRST 2135 Result: 135 BUTFIRST [[JANUARY FEBRUARY][MARCH APRIL] [MAY JUNE]] Result: [[MARCH APRIL] [MAY JUNE]]
BUTLAST
Also: BL
Reports all but the last element of its input; one input.
Syntax
BUTLAST word
BUTLAST list
Description
BUTLAST reports all but the last element of its input. If the input is a list, BUTLAST reports a list containing all but the last element. If the input is a word or number, BUTLAST reports all the characters of the word or number except the last character. See also BUTMEMBER, BUTFIRST, FIRST, and LAST.
The procedure in the example makes a plural word or list of words into singular form (for words that are made plural by adding the letter S).
Examples
TO SINGULAR :WORD IF EMPTY? :WORD THEN STOP PRINT BUTLAST FIRST :WORD SINGULAR BUTFIRST :WORD END Result: SINGULAR defined SINGULAR [CATS] Result: CAT SINGULAR [BOOKS TOOLS FLOWERS EYES RUNS] Result: BOOK TOOL FLOWER EYE RUN
BUTMEMBER
Also: BM, REMOVE
Removes elements from a word or a list; two inputs.
Syntax
BUTMEMBER word word
BUTMEMBER word.or.list list
Description
BUTMEMBER reports a word or list consisting of its second input with all occurrences of its first input removed. If the second input is a word, the first input must also be a word. If the second input is a list, the first input can be either a word or list.
See also BUTFIRST and BUTLAST.
Examples
BUTMEMBER “AM [HI I AM FRED] Result: [HI I FRED] BM “D “ABCDABCDABCD Result: ABCABCABC BUTMEMBER 22 [11 22 33 44 55] Result: [11 33 44 55] BUTMEMBER [JANUARY 1] [[JANUARY 1][JULY 4][DECEMBER 25]] Result: [[JULY 4][DECEMBER 25]]
CHAR
Converts a number into a Unicode character; one input.
Syntax
CHAR number
Description
CHAR reports the character whose Unicode code is the input. The input number can be from 0 through #H10FFFF (1114111). To output the Unicode code corresponding to an input character, use UNICODE.
Use caution when saving a Logo name or procedure that contains unprintable characters, like characters with a value of less than 32. Logo saves them as is without escaping them. If you, for example, save a value that contains a newline character (CHAR 10), then Logo may not be able to read that file correctly.
Examples
CHAR 20013 Result: 中
DATE
Reports the date; no inputs.
Syntax
DATE
Description
DATE reports the current date as a four-element list in the form [day month year dayofweek]. The dayofweek is a number from 1 to 7, starting at Sunday. Use TIME to get the current time.
Examples
DATE Result: [21 07 2025 5]
FIRST
Reports the first element of its input; one input.
Syntax
FIRST word
FIRST list
Description
FIRST reports the first element of its input. If the input is a word, FIRST reports the first character. If the input is a list, FIRST reports the first element of that list. If the word or list is empty, there is no first element, and FIRST throws an error. See also BUTFIRST, BUTLAST, and LAST.
Examples
FIRST [MARY HAD A LITTLE LAMB] Result: MARY FIRST “WHEAT Result: W FIRST 2135 Result: 2
FLATTEN
Reports a flat version of its list input; one input.
Syntax
FLATTEN list
Description
FLATTEN takes a list as its input and converts it to a flat list. The elements of all sublists in the list are appended to that flat list, as are the elements of their sublists. If FLATTEN is called with an input that is not a list, FLATTEN reports its input.
Examples
FLATTEN [HI [[LUCY ANN] SMITH]] Result: [HI LUCY ANN SMITH] FLATTEN 123 Result: 123
FPUT
Prepends an element to its input; two inputs.
Syntax
FPUT word word
FPUT word list
FPUT list list
Description
FPUT reports the word or list that is created by putting the first input at the beginning of the second input. If both inputs are words, FPUT reports a word; otherwise it reports a list. See also LIST, LPUT, SENTENCE, and WORD.
Examples
FPUT “A “BC Result: ABC FPUT 1 23 Result: 123 FPUT “A [GREEN CHEVY] Result: [A GREEN CHEVY] FPUT [NORTH DAKOTA] [NEW HAMPSHIRE] Result: [[NORTH DAKOTA] NEW HAMPSHIRE]
FROMMEMBER
Also: FM
Removes the first part of its input until a specified word or list is found; two inputs.
Syntax
FROMMEMBER word word
FROMMEMBER wordorlist list
Description
FROMMEMBER reports a word or list consisting of its second input with all elements removed up until the first occurrence of its first input. If the second input is a word, the first input must also be a word. If the second input is a list, the first input can be either a word or a list.
Examples
FROMMEMBER “B “ABC Result: BC FROMMEMBER 3 [1 2 3 4 5] Result: [3 4 5] FROMMEMBER “HAT “MANHATTAN Result: HATTAN FM “CHARLIE [ARCHIE BETSY CHARLIE DINAH EDWARD FRANCIS] Result: [CHARLIE DINAH EDWARD FRANCIS]
ISEQ
Outputs a list of sequential integers; expects between two inputs and three inputs, but parentheses are needed if not called with two inputs.
Syntax
ISEQ from to
(ISEQ from to increment)
Description
ISEQ outputs a list of the integers from “from” to “to”, inclusive. If an increment is given as an optional third input, the integers are created using the given increment; if no increment is given, the increment is 1 if “from” is less than “to”, or -1 if “from” is greater than “to”. Note that if the increment is not 1 or -1, the “to” value may not be part of the list; for example, the output of (ISEQ 1 5 3) would not contain the value 5, because the next value to add would have been 6 instead of 5.
Examples
ISEQ 5 10 Result: [5 6 7 8 9 10] ISEQ 10 5 Result: [10 9 8 7 6 5] (ISEQ 5 10 2) Result: [5 7 9]
ITEM
Returns a specific element of its input; two inputs.
Syntax
ITEM number word
ITEM number list
Description
ITEM reports the nth element from the second input where n is the first input (1), an integer, and the second input is a number, word, or list.
Examples
ITEM 3 “CAT Result: T ITEM 2 753 Result: 5 ITEM 3 [IN AT ON] Result: ON
JOIN
Converts a list to a word; two inputs.
Syntax
JOIN list separator
Description
JOIN concatenates each element of the list it receives as its first input and inserts the separator given as the second input between each list element. It reports the resulting word.
Use SPLIT to convert a JOINed word into a list.
Examples
JOIN [A B C D E] “| is | Result: A is B is C is D is E SPLIT “A,B,C,D,E “, Result: [A B C D E]
LAST
Reports the last element of its input; one input.
Syntax
LAST word
LAST list
Description
LAST reports the last element of its input. If the input is a word, LAST reports the last character. If the input is a list, LAST reports the last element of that list. If the word or list is empty, there is no last element, and LAST throws an error. See also BUTFIRST, BUTLAST, and FIRST.
Examples
LAST [MARY HAD A LITTLE LAMB] Result: LAMB LAST “WHEAT Result: T LAST 2135 Result: 5
LIST
Concatenates its inputs to a list; expects a minimum of one input, but parentheses are needed if not called with two inputs.
Syntax
LIST object1 object2
(LIST object1 object2 object3 ...)
Description
LIST reports a list composed of its inputs. The inputs to LIST can be either words or lists. If the inputs to LIST are themselves lists, LIST preserves them as lists. LIST expects two inputs, but can accept more or fewer if it and all its inputs are enclosed in parentheses. See also FPUT, LPUT, SENTENCE, and WORD.
To create a list enclosed in parentheses, use the XLIST command.
Examples
LIST “NORTH “CAROLINA Result: [NORTH CAROLINA] LIST [TO BE] [OR NOT TO BE] Result: [[TO BE] [OR NOT TO BE]]
LOCAL
Declares local variables inside a procedure; expects a minimum of one input, but parentheses are needed if not called with one input.
Syntax
LOCAL name
(LOCAL name1 name2 ...)
Description
LOCAL defines its input as a local variable whose value affects only the procedure in which it is called. The variable’s previous value (if any) is saved at the beginning of the procedure where it is redefined and restored at the end of the procedure. The variable is only available within the procedure in which it is defined and in all other procedures that are called from within the procedure where the variable is defined. The inputs to LOCAL must be quoted words.
Initially, a local name does not have a value. An attempt to read from a freshly declared local name causes a runtime error.
LOCALMAKE
Also: LMAKE
Create and set a local name; two inputs.
Syntax
LMAKE varname value
Description
LMAKE works in two ways. The first time LMAKE varname value is used in a procedure, Logo creates a new local name varname and assigns value to the local varname. This is the same as [LOCAL](cmd:LOCAL) varname MAKE varname value. For all subsequent uses of LMAKE varname value, Logo just uses the existing local varname. This is the same as MAKE varname value. The important thing to consider about LMAKE is that it ensures that the variable being referenced is local (by either creating a new local variable or using an existing local variable).
See also LOCAL, MAKE and THING.
Examples
MAKE “X “TOP TO TESTX LMAKE “X “INSIDE OUTPUT :X END TESTX defined TESTX Result: INSIDE :X Result: TOP
LOWERCASE
Converts its argument to lower case; one input.
Syntax
LOWERCASE word
Description
LOWERCASE converts its input to lower case. See also MIXEDCASE and UPPERCASE.
Examples
LOWERCASE “HELLO Result: hello LOWERCASE “|Hello| Result: hello
LPUT
Appends an element to its input; two inputs.
Syntax
LPUT word word
LPUT word list
LPUT list list
Description
LPUT reports a new object that is created by placing the first input at the end of the second input. The inputs to LPUT can be either words or lists. If the first input is a list, the second cannot be a word. If both inputs are words, LPUT reports a word. See also LIST, FPUT, SENTENCE, and WORD.
Examples
LPUT “ISSIPPI “MISS Result: MISSISSIPPI LPUT [COLORADO] [MISS] Result: [MISS [COLORADO]] LPUT FIRST [X Y Z] [A B C D] Result: [A B C D X]
MAKE
Assigns a value to a name; two inputs.
Syntax
MAKE name data
Description
MAKE defines a variable using the name of the first input and assigns the second input as the value of that variable. Once you have created the variable, you may obtain its contents by using :name. Think of the colon (:) as the value of name. To keep a variable local to the procedure in which MAKE is used, see LOCAL or LMAKE.
Remember that all local names of a procedure are visible to any procedure; a MAKE command may, therefore, set a name that is local to a procedure that is calling the current procedure if you use MAKE inside a procedure. See also NAME and THING.
Examples
MAKE “NUMBER 73 :NUMBER Result: 73
MILLISECONDS
Outputs the number of milliseconds spent; no inputs.
Syntax
MILLISECONDS
Description
MILLISECONDS outputs the number of milliseconds spent since the document loaded. MILLISECONDS can be used to track execution times. The accuracy of this timer is supposed to be at least 5 microseconds, but depends on the browser and operating system. Also, it is not guaranteed that the timer started running when the document has been loaded.
MIXEDCASE
Converts its argument to mixed case; one input.
Syntax
MIXEDCASE word
Description
MIXEDCASE converts its input to mixed case. Every word of its input starts with an upper case letter, while the remainder of the word is lower case. See also LOWERCASE and UPPERCASE.
Examples
MIXEDCASE “HELLO Result: Hello MIXEDCASE “|hello world| Result: Hello World
NAME
Assigns a value to a name; two inputs.
Syntax
NAME data name
Description
NAME defines a variable by assigning the value of the first input to the name of the second input. Once you have created the variable, you may obtain its contents by using :name. Think of the colon (:) as the value of name. NAME is equivalent to MAKE except that inputs are in reverse order. See also LOCAL.
Examples
NAME 5 “FIVE :FIVE Result: 5
PARSE
Parses a string and outputs a list; one input.
Syntax
PARSE word
Description
PARSE reads its input and converts it to a list.
The Listener procedure that Logo uses to evaluate user input is roughly written as:
TO LISTENER<br>RUN [PARSE READQUOTE]<br>END
Examples
PARSE “|hi world| Result: [HI WORLD] PARSE “|(a b c)| Result: [(A B C)]
PICK
Randomly picks an element; one input.
Syntax
PICK object
Description
PICK picks a randomly selected element from its input, a word or list.
Examples
MAKE “MUSIC [JAZZ POP ROCK CLASSICAL] PICK :MUSIC Result: POP PICK :MUSIC Result: CLASSICAL PICK “ABCDE Result: D PICK “ABCDE Result: B
QUOTE
Quotes its input; one input.
Syntax
QUOTE word
Description
QUOTE quotes its input. Lists are returned unchanged.
Examples
MAKE “FIRSTNAME “JOHN :FIRSTNAME Result: JOHN QUOTE :FIRSTNAME Result: “JOHN
RSEQ
Outputs a list of equally spaced rational numbers; three inputs.
Syntax
RSEQ from to count
Description
RSEQ outputs a list of “count” equally spaced rational numbers between “from” and “to”, inclusive.
Examples
RSEQ 4 5 6 Result: [4 4.2 4.4 4.6 4.8 5]
SENTENCE
Also: SE
Concatenates its inputs to a list, flattening lists; expects a minimum of one input, but parentheses are needed if not called with two inputs.
Syntax
SENTENCE object1 object2
(SE object1 object2 object3 ...)
Description
SENTENCE reports a list made up of its inputs. SENTENCE expects two inputs, but will accept more if it and all of its inputs are enclosed in parentheses. If the inputs to SENTENCE are lists, their brackets are removed and combined into one list. See also FPUT, LPUT, LIST, and WORD.
Examples
SENTENCE “NICEST “MONTH Result: [NICEST MONTH] SENTENCE [APRIL IS THE][NICEST MONTH] Result: [APRIL IS THE NICEST MONTH]
SPLIT
Splits a word into a list using a separator; two inputs.
Syntax
SPLIT word separator
Description
SPLIT uses the separator character(s) given as its second input to split a word into a list of words. Use JOIN to convert such a list back to a word.
Examples
SPLIT “A,B,C,D,E “, Result: [A B C D E] JOIN [A B C D E] “| is | Result: A is B is C is D is E
SUBST
Substitutes text in a word or a list; three inputs.
Syntax
SUBST what with wordorlist
Description
SUBST performs a replacement of text in its arguments. It replaces all occurrences of its first input with its second input inside the word or list given as its third input. If the third input is a list, the replacement is recursive and affects all lists inside the list. If the list element to be replaced is quoted, the replaced text remains quoted. In the same way, leading colons are preserved.
Examples
; Quotes and colons are preserved. SUBST “JUNK “NEW [A JUNK BOX] Result: [A NEW BOX] SUBST “? “X “A?B?C Result: AXBXC SUBST “? “MIKE [HELLO ? [HOW ARE YOU ?]] Result: [HELLO MIKE [HOW ARE YOU MIKE]]
THING
Reports the value of a name; one input.
Syntax
THING word
Description
THING reports the value associated with the variable named in the input. THING is the Logo primitive that does the same job as : (dots). It can be used to give a variable a second level of evaluation. A variable name could, for example, be passed to a procedure, and the procedure obtains its value with the THING command. Remember that Logo makes all names in a procedure visible to a procedure that this procedure calls. Therefore, getting a value may result in getting the value of a name that is local to a calling procedure.
Examples
MAKE “COLOR “BLUE MAKE “BLUE “AQUAMARINE THING “COLOR Result: BLUE THING :COLOR Result: AQUAMARINE THING “BLUE Result: AQUAMARINE THING :BLUE Result: :AQUAMARINE is not a name
TIME
Outputs the time; no inputs.
Syntax
TIME
Description
TIME reports the current time as a list of three numbers in the form [hour minute second]. The hours are in 24-hour format. See also DATE.
Examples
TIME Result: [10 35 50]
UPPERCASE
Converts its argument to upper case; one input.
Syntax
UPPERCASE word
Description
UPPERCASE converts its input to upper case. See also LOWERCASE and MIXEDCASE.
Examples
PR UPPERCASE “HELLO Result: HELLO PR UPPERCASE “|hello world| Result: HELLO WORLD
VERINFO
Outputs Logo version information as a list; no inputs.
Syntax
VERINFO
Description
VERINFO reports information about the version of Logo that is currently running as a list. The elements are major version number, minor version number, subrelease number, the name of the Logo program, the build date as a string, and the name of the operating system.
Examples
VERINFO Result: [6 0 252490 Terrapin Logo 2025/09/06 08:44:46 Windows WEB]
VERSION
Also: VER
Outputs the Logo version; no inputs.
Syntax
VERSION
Description
VERSION reports information about the version of Logo that is currently running.
Examples
VERSION Result: Terrapin Logo Windows (Web) Logo 6.0.252490 2025/09/06 08:44:46 Help 6.0.252490
WORD
Concatenates its inputs to a word; expects a minimum of one input, but parentheses are needed if not called with two inputs.
Syntax
WORD object1 object2
(WORD object1 object2 object3 ...)
Description
WORD concatenates its inputs, which must not be lists, to a single word.
Examples
WORD “NICEST “MONTH Result: NICESTMONTH
XLIST
Concatenates its inputs to a parenthesized list; expects between one input and two inputs, but parentheses are needed if not called with two inputs.
Syntax
XLIST object1 object2
(XLIST object1 object2 object3 ...)
Description
XLIST reports an executable list composed of its inputs. The inputs to XLIST can be either words or lists. If the inputs to XLIST are themselves lists, XLIST preserves them as lists. XLIST expects two inputs, but can accept more or fewer if it and all its inputs are enclosed in parentheses.
An executable list is a list enclosed in parentheses. To create a normal list, use the LIST command.
Examples
; This example creates a runlist containing a SENTENCE ; command with three instead of two inputs. This commands needs to be ;enclosed in parentheses so Logo can pick up all inputs. (LIST (XLIST “SENTENCE 1 2 3)) Result: [(SENTENCE 1 2 3)] RUN (LIST (XLIST “SENTENCE 1 2 3)) Result: [1 2 3]