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79. stringproc


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79.1 Introduction to String Processing

stringproc.lisp enlarges Maximas capabilities of working with strings and adds some useful functions for file in/output.

For questions and bugs please mail to volkervannek at gmail dot com .

In Maxima a string is easily constructed by typing "text". stringp tests for strings.

(%i1) m: "text";
(%o1)                         text
(%i2) stringp(m);
(%o2)                         true

Characters are represented as strings of length 1. These are not Lisp characters. Tests can be done with charp (respectively lcharp and conversion from Lisp to Maxima characters with cunlisp).

(%i1) c: "e";
(%o1)                           e
(%i2) [charp(c),lcharp(c)];
(%o2)                     [true, false]
(%i3) supcase(c);
(%o3)                           E
(%i4) charp(%);
(%o4)                         true

All functions in stringproc.lisp that return characters, return Maxima-characters. Due to the fact, that the introduced characters are strings of length 1, you can use a lot of string functions also for characters. As seen, supcase is one example.

It is important to know, that the first character in a Maxima-string is at position 1. This is designed due to the fact that the first element in a Maxima-list is at position 1 too. See definitions of charat and charlist for examples.

In applications string-functions are often used when working with files. You will find some useful stream- and print-functions in stringproc.lisp. The following example shows some of the here introduced functions at work.

Example:

openw returns an output stream to a file, printf then allows formatted writing to this file. See printf for details.

(%i1) s: openw("E:/file.txt");
(%o1)                    #<output stream E:/file.txt>
(%i2) for n:0 thru 10 do printf( s, "~d ", fib(n) );
(%o2)                                done
(%i3) printf( s, "~%~d ~f ~a ~a ~f ~e ~a~%", 
              42,1.234,sqrt(2),%pi,1.0e-2,1.0e-2,1.0b-2 );
(%o3)                                false
(%i4) close(s);
(%o4)                                true

After closing the stream you can open it again, this time with input direction. readline returns the entire line as one string. The stringproc package now offers a lot of functions for manipulating strings. Tokenizing can be done by split or tokens.

(%i5) s: openr("E:/file.txt");
(%o5)                     #<input stream E:/file.txt>
(%i6) readline(s);
(%o6)                     0 1 1 2 3 5 8 13 21 34 55 
(%i7) line: readline(s);
(%o7)               42 1.234 sqrt(2) %pi 0.01 1.0E-2 1.0b-2
(%i8) list: tokens(line);
(%o8)           [42, 1.234, sqrt(2), %pi, 0.01, 1.0E-2, 1.0b-2]
(%i9) map( parse_string, list );
(%o9)            [42, 1.234, sqrt(2), %pi, 0.01, 0.01, 1.0b-2]
(%i10) float(%);
(%o10) [42.0, 1.234, 1.414213562373095, 3.141592653589793, 0.01,
                                                     0.01, 0.01]
(%i11) readline(s);
(%o11)                               false
(%i12) close(s)$

readline returns false when the end of file occurs.

Categories:  Strings · Share packages · Package stringproc


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79.2 Input and Output

Example:

(%i1) s: openw("E:/file.txt");
(%o1)                     #<output stream E:/file.txt>
(%i2) control: 
"~2tAn atom: ~20t~a~%~2tand a list: ~20t~{~r ~}~%~2t\
and an integer: ~20t~d~%"$
(%i3) printf( s,control, 'true,[1,2,3],42 )$
(%o3)                                false
(%i4) close(s);
(%o4)                                true
(%i5) s: openr("E:/file.txt");
(%o5)                     #<input stream E:/file.txt>
(%i6) while stringp( tmp:readline(s) ) do print(tmp)$
  An atom:          true 
  and a list:       one two three  
  and an integer:   42 
(%i7) close(s)$

Function: close (stream)

Closes stream and returns true if stream had been open.

Function: flength (stream)

stream has to be an open stream from or to a file. flength then returns the number of bytes which are currently present in this file.

Example: See writebyte .

Function: flush_output (stream)

Flushes stream where stream has to be an output stream to a file.

Example: See writebyte .

Categories:  File output · Package stringproc

Function: fposition  
    fposition (stream)  
    fposition (stream, pos)

Returns the current position in stream, if pos is not used. If pos is used, fposition sets the position in stream. stream has to be a stream from or to a file and pos has to be a positive number where the first element in stream is in position 1.

Function: freshline  
    freshline ()  
    freshline (stream)

Writes a new line (to stream), if the position is not at the beginning of a line. See also newline.

Categories:  File output · Package stringproc

Function: get_output_stream_string (stream)

Returns a string containing all the characters currently present in stream which must be an open string-output stream. The returned characters are removed from stream.

Example: See make_string_output_stream .

Categories:  Package stringproc

Function: make_string_input_stream  
    make_string_input_stream (string)  
    make_string_input_stream (string, start)  
    make_string_input_stream (string, start, end)

Returns an input stream which contains parts of string and an end of file. Without optional arguments the stream contains the entire string and is positioned in front of the first character. start and end define the substring contained in the stream. The first character is available at position 1.

(%i1) istream : make_string_input_stream("text", 1, 4);
(%o1)              #<string-input stream from "text">
(%i2) (while (c : readchar(istream)) # false do sprint(c), newline())$
t e x 
(%i3) close(istream)$

Categories:  Package stringproc

Function: make_string_output_stream ()

Returns an output stream that accepts characters. Characters currently present in this stream can be retrieved by get_output_stream_string.

(%i1) ostream : make_string_output_stream();
(%o1)               #<string-output stream 09622ea0>
(%i2) printf(ostream, "foo")$

(%i3) printf(ostream, "bar")$

(%i4) string : get_output_stream_string(ostream);
(%o4)                            foobar
(%i5) printf(ostream, "baz")$

(%i6) string : get_output_stream_string(ostream);
(%o6)                              baz
(%i7) close(ostream)$

Categories:  Package stringproc

Function: newline  
    newline ()  
    newline (stream)

Writes a new line (to stream). See sprint for an example of using newline(). Note that there are some cases, where newline() does not work as expected.

Categories:  File output · Package stringproc

Function: opena (file)

Returns a character output stream to file. If an existing file is opened, opena appends elements at the end of file.

For binary output see opena_binary .

Categories:  File output · Package stringproc

Function: openr (file)

Returns a character input stream to file. openr assumes that file already exists.

For binary input see openr_binary .

Categories:  File input · Package stringproc

Function: openw (file)

Returns a character output stream to file. If file does not exist, it will be created. If an existing file is opened, openw destructively modifies file.

For binary output see openw_binary .

Categories:  File output · Package stringproc

Function: printf  
    printf (dest, string)  
    printf (dest, string, expr_1, ..., expr_n)

Produces formatted output by outputting the characters of control-string string and observing that a tilde introduces a directive. The character after the tilde, possibly preceded by prefix parameters and modifiers, specifies what kind of formatting is desired. Most directives use one or more elements of the arguments expr_1, ..., expr_n to create their output.

If dest is a stream or true, then printf returns false. Otherwise, printf returns a string containing the output.

printf provides the Common Lisp function format in Maxima. The following example illustrates the general relation between these two functions.

(%i1) printf(true, "R~dD~d~%", 2, 2);
R2D2
(%o1)                                false
(%i2) :lisp (format t "R~dD~d~%" 2 2)
R2D2
NIL

The following description is limited to a rough sketch of the possibilities of printf. The Lisp function format is described in detail in many reference books. Of good help is e.g. the free available online-manual "Common Lisp the Language" by Guy L. Steele. See chapter 22.3.3 there.

   ~%       new line
   ~&       fresh line
   ~t       tab
   ~$       monetary
   ~d       decimal integer
   ~b       binary integer
   ~o       octal integer
   ~x       hexadecimal integer
   ~br      base-b integer
   ~r       spell an integer
   ~p       plural
   ~f       floating point
   ~e       scientific notation
   ~g       ~f or ~e, depending upon magnitude
   ~h       bigfloat
   ~a       uses Maxima function string
   ~s       like ~a, but output enclosed in "double quotes"
   ~~       ~
   ~<       justification, ~> terminates
   ~(       case conversion, ~) terminates 
   ~[       selection, ~] terminates 
   ~{       iteration, ~} terminates

The directive ~h for bigfloat is no Lisp-standard and is therefore illustrated below.

Note that the directive ~* is not supported.

If dest is a stream or true, then printf returns false. Otherwise, printf returns a string containing the output.

(%i1) printf( false, "~a ~a ~4f ~a ~@r", 
              "String",sym,bound,sqrt(12),144), bound = 1.234;
(%o1)                 String sym 1.23 2*sqrt(3) CXLIV
(%i2) printf( false,"~{~a ~}",["one",2,"THREE"] );
(%o2)                          one 2 THREE 
(%i3) printf(true,"~{~{~9,1f ~}~%~}",mat ),
          mat = args(matrix([1.1,2,3.33],[4,5,6],[7,8.88,9]))$
      1.1       2.0       3.3 
      4.0       5.0       6.0 
      7.0       8.9       9.0 
(%i4) control: "~:(~r~) bird~p ~[is~;are~] singing."$
(%i5) printf( false,control, n,n,if n=1 then 1 else 2 ), n=2;
(%o5)                    Two birds are singing.

The directive ~h has been introduced to handle bigfloats.

~w,d,e,x,o,p@H
 w : width
 d : decimal digits behind floating point
 e : minimal exponent digits
 x : preferred exponent
 o : overflow character
 p : padding character
 @ : display sign for positive numbers
(%i1) fpprec : 1000$
(%i2) printf(true, "|~h|~%", 2.b0^-64)$
|0.0000000000000000000542101086242752217003726400434970855712890625|
(%i3) fpprec : 26$
(%i4) printf(true, "|~h|~%", sqrt(2))$
|1.4142135623730950488016887|
(%i5) fpprec : 24$
(%i6) printf(true, "|~h|~%", sqrt(2))$
|1.41421356237309504880169|
(%i7) printf(true, "|~28h|~%", sqrt(2))$
|   1.41421356237309504880169|
(%i8) printf(true, "|~28,,,,,'*h|~%", sqrt(2))$
|***1.41421356237309504880169|
(%i9) printf(true, "|~,18h|~%", sqrt(2))$
|1.414213562373095049|
(%i10) printf(true, "|~,,,-3h|~%", sqrt(2))$
|1414.21356237309504880169b-3|
(%i11) printf(true, "|~,,2,-3h|~%", sqrt(2))$
|1414.21356237309504880169b-03|
(%i12) printf(true, "|~20h|~%", sqrt(2))$
|1.41421356237309504880169|
(%i13) printf(true, "|~20,,,,'+h|~%", sqrt(2))$
|++++++++++++++++++++|

Categories:  File output · Package stringproc

Function: readbyte (stream)

Removes and returns the first byte in stream which must be a binary input stream. If the end of file is encountered readbyte returns false.

Example: Read the first 16 bytes from a file encrypted with AES in OpenSSL.

(%i1) ibase: obase: 16.$

(%i2) in: openr_binary("msg.bin");
(%o2)                       #<input stream msg.bin>
(%i3) (L:[],  thru 16. do push(readbyte(in), L),  L:reverse(L));
(%o3) [53, 61, 6C, 74, 65, 64, 5F, 5F, 88, 56, 0DE, 8A, 74, 0FD, 0AD, 0F0]
(%i4) close(in);
(%o4)                                true
(%i5) map(ascii, rest(L,-8));
(%o5)                      [S, a, l, t, e, d, _, _]
(%i6) salt: octets_to_number(rest(L,8));
(%o6)                          8856de8a74fdadf0

Categories:  File input · Package stringproc

Function: readchar (stream)

Removes and returns the first character in stream. If the end of file is encountered readchar returns false.

Example: See make_string_input_stream.

Categories:  File input · Package stringproc

Function: readline (stream)

Returns a string containing the characters from the current position in stream up to the end of the line or false if the end of the file is encountered.

Categories:  File input · Package stringproc

Function: sprint (expr_1, …, expr_n)

Evaluates and displays its arguments one after the other `on a line' starting at the leftmost position. The expressions are printed with a space character right next to the number, and it disregards line length. newline() might be useful, if you whish to place intermediate line breaking.

Example:

(%i1) for n:0 thru 19 do sprint( fib(n) )$
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181
(%i2) for n:0 thru 22 do ( 
         sprint(fib(n)), if mod(n,10)=9 then newline() )$
0 1 1 2 3 5 8 13 21 34 
55 89 144 233 377 610 987 1597 2584 4181 
6765 10946 17711 

Categories:  Package stringproc

Function: writebyte (byte, stream)

Writes byte to stream which must be a binary output stream. writebyte returns byte.

Example: Write some bytes to a binary file output stream. In this example all bytes correspond to printable characters and are printed by printfile. The bytes remain in the stream until flush_output or close have been called.

(%i1) ibase: obase: 16.$

(%i2) bytes: map(cint, charlist("GNU/Linux"));
(%o2)                [47, 4E, 55, 2F, 4C, 69, 6E, 75, 78]
(%i3) out: openw_binary("test.bin");
(%o3)                      #<output stream test.bin>
(%i4) for i thru 3 do writebyte(bytes[i], out);
(%o4)                                done
(%i5) printfile("test.bin")$

(%i6) flength(out);
(%o6)                                  0
(%i7) flush_output(out);
(%o7)                                true
(%i8) flength(out);
(%o8)                                  3
(%i9) printfile("test.bin")$
GNU
(%i0A) for b in rest(bytes,3) do writebyte(b, out);
(%o0A)                               done
(%i0B) close(out);
(%o0B)                               true
(%i0C) printfile("test.bin")$
GNU/Linux

Categories:  File output · Package stringproc


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79.3 Characters

Function: alphacharp (char)

Returns true if char is an alphabetic character.

Function: alphanumericp (char)

Returns true if char is an alphabetic character or a digit.

Function: ascii (int)

Returns the character corresponding to the ASCII number int. ( -1 < int < 256 )

(%i1) for n from 0 thru 255 do ( 
   tmp: ascii(n), if alphacharp(tmp) then sprint(tmp),
      if n=96 then newline() )$
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
a b c d e f g h i j k l m n o p q r s t u v w x y z

Categories:  Package stringproc

Function: cequal (char_1, char_2)

Returns true if char_1 and char_2 are the same.

Function: cequalignore (char_1, char_2)

Like cequal but ignores case.

Function: cgreaterp (char_1, char_2)

Returns true if the ASCII number of char_1 is greater than the number of char_2.

Function: cgreaterpignore (char_1, char_2)

Like cgreaterp but ignores case.

Function: charp (obj)

Returns true if obj is a Maxima-character. See introduction for example.

Function: cint (char)

Returns the ASCII number of char.

Categories:  Package stringproc

Function: clessp (char_1, char_2)

Returns true if the ASCII number of char_1 is less than the number of char_2.

Function: clesspignore (char_1, char_2)

Like clessp but ignores case.

Function: constituent (char)

Returns true if char is a graphic character and not the space character. A graphic character is a character one can see, plus the space character. (constituent is defined by Paul Graham, ANSI Common Lisp, 1996, page 67.)

(%i1) for n from 0 thru 255 do ( 
tmp: ascii(n), if constituent(tmp) then sprint(tmp) )$
! " #  %  ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ A B
C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ` a b c
d e f g h i j k l m n o p q r s t u v w x y z { | } ~

Function: cunlisp (lisp_char)

Converts a Lisp-character into a Maxima-character. (You won't need it.)

Categories:  Package stringproc

Function: digitcharp (char)

Returns true if char is a digit.

Function: lcharp (obj)

Returns true if obj is a Lisp-character. (You won't need it.)

Function: lowercasep (char)

Returns true if char is a lowercase character.

Variable: newline

The newline character.

Variable: space

The space character.

Variable: tab

The tab character.

Function: uppercasep (char)

Returns true if char is an uppercase character.


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79.4 String Processing

Function: charat (string, n)

Returns the n-th character of string. The first character in string is returned with n = 1.

(%i1) charat("Lisp",1);
(%o1)                           L

Categories:  Package stringproc

Function: charlist (string)

Returns the list of all characters in string.

(%i1) charlist("Lisp");
(%o1)                     [L, i, s, p]
(%i2) %[1];
(%o2)                           L

Categories:  Package stringproc

Function: eval_string (str)

Parse the string str as a Maxima expression and evaluate it. The string str may or may not have a terminator (dollar sign $ or semicolon ;). Only the first expression is parsed and evaluated, if there is more than one.

Complain if str is not a string.

Examples:

(%i1) eval_string ("foo: 42; bar: foo^2 + baz");
(%o1)                       42
(%i2) eval_string ("(foo: 42, bar: foo^2 + baz)");
(%o2)                   baz + 1764

See also parse_string.

Categories:  Package stringproc

Function: parse_string (str)

Parse the string str as a Maxima expression (do not evaluate it). The string str may or may not have a terminator (dollar sign $ or semicolon ;). Only the first expression is parsed, if there is more than one.

Complain if str is not a string.

Examples:

(%i1) parse_string ("foo: 42; bar: foo^2 + baz");
(%o1)                    foo : 42
(%i2) parse_string ("(foo: 42, bar: foo^2 + baz)");
                                   2
(%o2)          (foo : 42, bar : foo  + baz)

See also eval_string.

Categories:  Package stringproc

Function: scopy (string)

Returns a copy of string as a new string.

Categories:  Package stringproc

Function: sdowncase  
    sdowncase (string)  
    sdowncase (string, start)  
    sdowncase (string, start, end)

Like supcase, but uppercase characters are converted to lowercase.

Categories:  Package stringproc

Function: sequal (string_1, string_2)

Returns true if string_1 and string_2 are the same length and contain the same characters.

Function: sequalignore (string_1, string_2)

Like sequal but ignores case.

Function: sexplode (string)

sexplode is an alias for function charlist.

Categories:  Package stringproc

Function: simplode  
    simplode (list)  
    simplode (list, delim)

simplode takes a list of expressions and concatenates them into a string. If no delimiter delim is specified, simplode uses no delimiter. delim can be any string.

(%i1) simplode(["xx[",3,"]:",expand((x+y)^3)]);
(%o1)             xx[3]:y^3+3*x*y^2+3*x^2*y+x^3
(%i2) simplode( sexplode("stars")," * " );
(%o2)                   s * t * a * r * s
(%i3) simplode( ["One","more","coffee."]," " );
(%o3)                   One more coffee.

Categories:  Package stringproc

Function: sinsert (seq, string, pos)

Returns a string that is a concatenation of substring (string, 1, pos - 1), the string seq and substring (string, pos). Note that the first character in string is in position 1.

(%i1) s: "A submarine."$
(%i2) concat( substring(s,1,3),"yellow ",substring(s,3) );
(%o2)                  A yellow submarine.
(%i3) sinsert("hollow ",s,3);
(%o3)                  A hollow submarine.

Categories:  Package stringproc

Function: sinvertcase  
    sinvertcase (string)  
    sinvertcase (string, start)  
    sinvertcase (string, start, end)

Returns string except that each character from position start to end is inverted. If end is not given, all characters from start to the end of string are replaced.

(%i1) sinvertcase("sInvertCase");
(%o1)                      SiNVERTcASE

Categories:  Package stringproc

Function: slength (string)

Returns the number of characters in string.

Categories:  Package stringproc

Function: smake (num, char)

Returns a new string with a number of num characters char.

(%i1) smake(3,"w");
(%o1)                          www

Categories:  Package stringproc

Function: smismatch  
    smismatch (string_1, string_2)  
    smismatch (string_1, string_2, test)

Returns the position of the first character of string_1 at which string_1 and string_2 differ or false. Default test function for matching is sequal. If smismatch should ignore case, use sequalignore as test.

(%i1) smismatch("seven","seventh");
(%o1)                           6

Categories:  Package stringproc

Function: split  
    split (string)  
    split (string, delim)  
    split (string, delim, multiple)

Returns the list of all tokens in string. Each token is an unparsed string. split uses delim as delimiter. If delim is not given, the space character is the default delimiter. multiple is a boolean variable with true by default. Multiple delimiters are read as one. This is useful if tabs are saved as multiple space characters. If multiple is set to false, each delimiter is noted.

(%i1) split("1.2   2.3   3.4   4.5");
(%o1)                 [1.2, 2.3, 3.4, 4.5]
(%i2) split("first;;third;fourth",";",false);
(%o2)               [first, , third, fourth]

Categories:  Package stringproc

Function: sposition (char, string)

Returns the position of the first character in string which matches char. The first character in string is in position 1. For matching characters ignoring case see ssearch.

Categories:  Package stringproc

Function: sremove  
    sremove (seq, string)  
    sremove (seq, string, test)  
    sremove (seq, string, test, start)  
    sremove (seq, string, test, start, end)

Returns a string like string but without all substrings matching seq. Default test function for matching is sequal. If sremove should ignore case while searching for seq, use sequalignore as test. Use start and end to limit searching. Note that the first character in string is in position 1.

(%i1) sremove("n't","I don't like coffee.");
(%o1)                   I do like coffee.
(%i2) sremove ("DO ",%,'sequalignore);
(%o2)                    I like coffee.

Categories:  Package stringproc

Function: sremovefirst  
    sremovefirst (seq, string)  
    sremovefirst (seq, string, test)  
    sremovefirst (seq, string, test, start)  
    sremovefirst (seq, string, test, start, end)

Like sremove except that only the first substring that matches seq is removed.

Categories:  Package stringproc

Function: sreverse (string)

Returns a string with all the characters of string in reverse order.

Categories:  Package stringproc

Function: ssearch  
    ssearch (seq, string)  
    ssearch (seq, string, test)  
    ssearch (seq, string, test, start)  
    ssearch (seq, string, test, start, end)

Returns the position of the first substring of string that matches the string seq. Default test function for matching is sequal. If ssearch should ignore case, use sequalignore as test. Use start and end to limit searching. Note that the first character in string is in position 1.

(%i1) ssearch("~s","~{~S ~}~%",'sequalignore);
(%o1)                                  4

Categories:  Package stringproc

Function: ssort  
    ssort (string)  
    ssort (string, test)

Returns a string that contains all characters from string in an order such there are no two successive characters c and d such that test (c, d) is false and test (d, c) is true. Default test function for sorting is clessp. The set of test functions is {clessp, clesspignore, cgreaterp, cgreaterpignore, cequal, cequalignore}.

(%i1) ssort("I don't like Mondays.");
(%o1)                    '.IMaddeiklnnoosty
(%i2) ssort("I don't like Mondays.",'cgreaterpignore);
(%o2)                 ytsoonnMlkIiedda.'   

Categories:  Package stringproc

Function: ssubst  
    ssubst (new, old, string)  
    ssubst (new, old, string, test)  
    ssubst (new, old, string, test, start)  
    ssubst (new, old, string, test, start, end)

Returns a string like string except that all substrings matching old are replaced by new. old and new need not to be of the same length. Default test function for matching is sequal. If ssubst should ignore case while searching for old, use sequalignore as test. Use start and end to limit searching. Note that the first character in string is in position 1.

(%i1) ssubst("like","hate","I hate Thai food. I hate green tea.");
(%o1)          I like Thai food. I like green tea.
(%i2) ssubst("Indian","thai",%,'sequalignore,8,12);
(%o2)         I like Indian food. I like green tea.

Categories:  Package stringproc

Function: ssubstfirst  
    ssubstfirst (new, old, string)  
    ssubstfirst (new, old, string, test)  
    ssubstfirst (new, old, string, test, start)  
    ssubstfirst (new, old, string, test, start, end)

Like subst except that only the first substring that matches old is replaced.

Categories:  Package stringproc

Function: strim (seq,string)

Returns a string like string, but with all characters that appear in seq removed from both ends.

(%i1) "/* comment */"$
(%i2) strim(" /*",%);
(%o2)                        comment
(%i3) slength(%);
(%o3)                           7

Categories:  Package stringproc

Function: striml (seq, string)

Like strim except that only the left end of string is trimmed.

Categories:  Package stringproc

Function: strimr (seq, string)

Like strim except that only the right end of string is trimmed.

Categories:  Package stringproc

Function: stringp (obj)

Returns true if obj is a string. See introduction for example.

Function: substring  
    substring (string, start)  
    substring (string, start, end)

Returns the substring of string beginning at position start and ending at position end. The character at position end is not included. If end is not given, the substring contains the rest of the string. Note that the first character in string is in position 1.

(%i1) substring("substring",4);
(%o1)                        string
(%i2) substring(%,4,6);
(%o2)                          in

Categories:  Package stringproc

Function: supcase  
    supcase (string)  
    supcase (string, start)  
    supcase (string, start, end)

Returns string except that lowercase characters from position start to end are replaced by the corresponding uppercase ones. If end is not given, all lowercase characters from start to the end of string are replaced.

(%i1) supcase("english",1,2);
(%o1)                        English

Categories:  Package stringproc

Function: tokens  
    tokens (string)  
    tokens (string, test)

Returns a list of tokens, which have been extracted from string. The tokens are substrings whose characters satisfy a certain test function. If test is not given, constituent is used as the default test. {constituent, alphacharp, digitcharp, lowercasep, uppercasep, charp, characterp, alphanumericp} is the set of test functions. (The Lisp-version of tokens is written by Paul Graham. ANSI Common Lisp, 1996, page 67.)

(%i1) tokens("24 October 2005");
(%o1)                  [24, October, 2005]
(%i2) tokens("05-10-24",'digitcharp);
(%o2)                     [05, 10, 24]
(%i3) map(parse_string,%);
(%o3)                      [5, 10, 24]

Categories:  Package stringproc


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79.5 Octets and Utilities for Cryptography

Function: base64 (arg)

Returns the base64-representation of arg as a string. The argument arg may be a string, a non-negative integer or a list of octets.

Example:

(%i1) base64: base64("foo bar baz");
(%o1)                          Zm9vIGJhciBiYXo=
(%i2) string: base64_decode(base64);
(%o2)                            foo bar baz
(%i3) obase: 16.$
(%i4) integer: base64_decode(base64, 'number);
(%o4)                       666f6f206261722062617a
(%i5) octets: base64_decode(base64, 'list);
(%o5)            [66, 6F, 6F, 20, 62, 61, 72, 20, 62, 61, 7A]
(%i6) ibase: 16.$
(%i7) base64(octets);
(%o7)                          Zm9vIGJhciBiYXo=

Note that if arg contains umlauts (resp. octets larger than 127) the resulting base64-string is platform dependend. However the decoded string will be equal to the original.

Categories:  Package stringproc

Function: base64_decode  
    base64_decode (base64-string)  
    base64_decode (base64-string, return-type)

By default base64_decode decodes the base64-string back to the original string.

The optional argument return-type allows base64_decode to alternatively return the corresponding number or list of octets.

Example: See base64.

Categories:  Package stringproc

Function: crc24sum  
    crc24sum (octets)  
    crc24sum (octets, return-type)

By default crc24sum returns the CRC24 checksum of an octet-list as a string.

The optional argument return-type allows crc24sum to alternatively return the corresponding number or list of octets.

Example:

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)

iQEcBAEBAgAGBQJVdCTzAAoJEG/1Mgf2DWAqCSYH/AhVFwhu1D89C3/QFcgVvZTM
wnOYzBUURJAL/cT+IngkLEpp3hEbREcugWp+Tm6aw3R4CdJ7G3FLxExBH/5KnDHi
rBQu+I7+3ySK2hpryQ6Wx5J9uZSa4YmfsNteR8up0zGkaulJeWkS4pjiRM+auWVe
vajlKZCIK52P080DG7Q2dpshh4fgTeNwqCuCiBhQ73t8g1IaLdhDN6EzJVjGIzam
/spqT/sTo6sw8yDOJjvU+Qvn6/mSMjC/YxjhRMaQt9EMrR1AZ4ukBF5uG1S7mXOH
WdiwkSPZ3gnIBhM9SuC076gLWZUNs6NqTeE3UzMjDAFhH3jYk1T7mysCvdtIkms=
=WmeC
-----END PGP SIGNATURE-----
(%i1) ibase : obase : 16.$
(%i2) sig64 : sconcat(
 "iQEcBAEBAgAGBQJVdCTzAAoJEG/1Mgf2DWAqCSYH/AhVFwhu1D89C3/QFcgVvZTM",
 "wnOYzBUURJAL/cT+IngkLEpp3hEbREcugWp+Tm6aw3R4CdJ7G3FLxExBH/5KnDHi",
 "rBQu+I7+3ySK2hpryQ6Wx5J9uZSa4YmfsNteR8up0zGkaulJeWkS4pjiRM+auWVe",
 "vajlKZCIK52P080DG7Q2dpshh4fgTeNwqCuCiBhQ73t8g1IaLdhDN6EzJVjGIzam",
 "/spqT/sTo6sw8yDOJjvU+Qvn6/mSMjC/YxjhRMaQt9EMrR1AZ4ukBF5uG1S7mXOH",
 "WdiwkSPZ3gnIBhM9SuC076gLWZUNs6NqTeE3UzMjDAFhH3jYk1T7mysCvdtIkms=" )$
(%i3) octets: base64_decode(sig64, 'list)$
(%i4) crc24: crc24sum(octets, 'list);
(%o4)                          [5A, 67, 82]
(%i5) base64(crc24);
(%o5)                              WmeC

Categories:  Package stringproc

Function: md5sum  
    md5sum (arg)  
    md5sum (arg, return-type)

Returns the MD5 checksum of a string, a non-negative integer or a list of octets. The default return value is a string containing 32 hex characters.

The optional argument return-type allows md5sum to alternatively return the corresponding number or list of octets.

Example:

(%i1) ibase: obase: 16.$
(%i2) msg: "foo bar baz"$
(%i3) string: md5sum(msg);
(%o3)                  ab07acbb1e496801937adfa772424bf7
(%i4) integer: md5sum(msg, 'number);
(%o4)                 0ab07acbb1e496801937adfa772424bf7
(%i5) octets: md5sum(msg, 'list);
(%o5)        [0AB,7,0AC,0BB,1E,49,68,1,93,7A,0DF,0A7,72,42,4B,0F7]
(%i6) sdowncase( printf(false, "~{~2,'0x~^:~}", octets) );
(%o6)           ab:07:ac:bb:1e:49:68:01:93:7a:df:a7:72:42:4b:f7

Note that in case arg contains German umlauts or other non-ASCII characters (resp. octets larger than 127) the MD5 checksum is platform dependend.

Categories:  Package stringproc

Function: number_to_octets (number)

Returns an octet-representation of number as a list of octets. The number must be a non-negative integer.

Example:

(%i1) ibase : obase : 16.$
(%i2) octets: [0ca,0fe,0ba,0be]$
(%i3) number: octets_to_number(octets);
(%o3)                            0cafebabe
(%i4) number_to_octets(number);
(%o4)                      [0CA, 0FE, 0BA, 0BE]

Categories:  Package stringproc

Function: octets_to_number (octets)

Returns a number by concatenating the octets in the list of octets.

Example: See number_to_octets.

Categories:  Package stringproc

Function: octets_to_oid (octets)

Computes an object identifier (OID) from the list of octets.

Example: RSA encryption OID

(%i1) ibase : obase : 16.$
(%i2) oid: octets_to_oid([2A,86,48,86,0F7,0D,1,1,1]);
(%o2)                      1.2.840.113549.1.1.1
(%i3) oid_to_octets(oid);
(%o3)               [2A, 86, 48, 86, 0F7, 0D, 1, 1, 1]

Categories:  Package stringproc

Function: oid_to_octets (oid-string)

Convertes an object identifier (OID) to a list of octets.

Example: See octets_to_oid.

Categories:  Package stringproc

Function: sha1sum  
    sha1sum (arg)  
    sha1sum (arg, return-type)

Returns the SHA1 fingerprint of a string, a non-negative integer or a list of octets. The default return value is a string containing 40 hex characters.

The optional argument return-type allows sha1sum to alternatively return the corresponding number or list of octets.

Example:

(%i1) ibase: obase: 16.$
(%i2) msg: "foo bar baz"$
(%i3) string: sha1sum(msg);
(%o3)              c7567e8b39e2428e38bf9c9226ac68de4c67dc39
(%i4) integer: sha1sum(msg, 'number);
(%o4)             0c7567e8b39e2428e38bf9c9226ac68de4c67dc39
(%i5) octets: sha1sum(msg, 'list);
(%o5)  [0C7,56,7E,8B,39,0E2,42,8E,38,0BF,9C,92,26,0AC,68,0DE,4C,67,0DC,39]
(%i6) sdowncase( printf(false, "~{~2,'0x~^:~}", octets) );
(%o6)     c7:56:7e:8b:39:e2:42:8e:38:bf:9c:92:26:ac:68:de:4c:67:dc:39

Note that in case arg contains German umlauts or other non-ASCII characters (resp. octets larger than 127) the SHA1 fingerprint is platform dependend.

Categories:  Package stringproc

Function: sha256sum  
    sha256sum (arg)  
    sha256sum (arg, return-type)

Returns the SHA256 fingerprint of a string, a non-negative integer or a list of octets. The default return value is a string containing 64 hex characters.

The optional argument return-type allows sha256sum to alternatively return the corresponding number or list of octets (see sha1sum).

Example:

(%i1) string: sha256sum("foo bar baz");
(%o1)  dbd318c1c462aee872f41109a4dfd3048871a03dedd0fe0e757ced57dad6f2d7

Note that in case arg contains German umlauts or other non-ASCII characters (resp. octets larger than 127) the SHA256 fingerprint is platform dependend.

Categories:  Package stringproc


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This document was generated by Robert Dodier on November, 9 2015 using texi2html 1.76.