## functions in std.i - r

random
```
random(dimension_list)
random_seed, seed

returns an array of random double values with the given
DIMENSION_LIST (nil for a scalar result), uniformly distributed
on the interval from 0.0 to 1.0.
The algorithm is from Press and Teukolsky, Computers in Physics,
vol. 6, no. 5, Sep/Oct 1992 (ran2).  They offer a reward of \$1000
to anyone who can exhibit a statistical test that this random
number generator fails in a "non-trivial" way.
The random_seed call reinitializes the random number sequence;
SEED should be between 0.0 and 1.0 non-inclusive; if SEED is
omitted, nil, or out of range, the sequence is reinitialized as
when Yorick starts.
The numbers are actually at the centers of 2147483562 equal width
bins on the interval [0,1].  Although only these 2 billion numbers
are possible, the period of the generator is roughly 2.3e18.
Builtin function, documented at i0/std.i   line 758

```

random_seed
```
random_seed

Builtin function, documented at i0/std.i   line 758

```
SEE random

randomize
```
randomize
randomize()

set the seed for random "randomly" (based on the timer clock
and the current state of random).  As a function, returns the
value of the seed passed to random_seed.
Interpreted function, defined at i0/std.i   line 780

```

rdfile
```
rdfile(f)
or rdfile(f, nmax)

reads all remaining lines (or at most NMAX lines) from file F.
If NMAX is omitted, it defaults to 2^20 lines (about a million).
The result is an array of strings, one per line of F.
Interpreted function, defined at i0/std.i   line 2110

```

rdline
```
rdline(f)
or rdline(f, n, prompt= pstring)

returns next line from stream F (stdin if F nil).  If N is non-nil,
returns a string array containing the next N lines of F.  If
end-of-file occurs, rdline returns nil strings.  If F is nil,
uses the PSTRING to prompt for input (default "read> ").
Builtin function, documented at i0/std.i   line 2100

```

re_part
```
re_part(z)

returns the real part of its argument.  (Same as double(z).)
Unlike z.re, works if z is not complex.
Keyword,  defined at i0/std.i   line 742

```

```
n= read(f, format=fstring, obj1, obj2, ...)
or n= read(prompt= pstring, format=fstring, obj1, obj2, ...)
or n= sread(source, format=fstring, obj1, obj2, ...)

reads text from I/O stream F (1st form), or from the keyboard (2nd
form), or from the string or string array SOURCE (3rd form),
interprets it according to the optional FSTRING, and uses that
interpretation to assign values to OBJ1, OBJ2, ...  If the input
is taken from the keyboard, the optional prompt PSTRING (default
"read> ") is printed before each line is read.  The Yorick write
function does not interact with the read function -- writes are
always to end-of-file, and do not affect the sequence of lines
returned by read.  The backup (and bookmark) function is the
only way to change the sequence of lines returned by read.
There must be one non-supressed conversion specifier (see below)
in FSTRING for each OBJ to be read; the type of the conversion
specifier must generally match the type of the OBJ.  That is,
an integer OBJ requires an integer specifier (d, i, o, u, or x)
in FSTRING, a real OBJ requires a real specifier (e, f, or g),
and a string OBJ requires a string specifier (s or []).  An OBJ
may not be complex, a pointer, a structure instance, or any non-
array Yorick object.  If FSTRING is not supplied, or if it has
fewer conversion specifiers than the number of OBJ arguments,
then Yorick supplies default specifiers ("%ld" for integers,
"%lg" for reals, and "%s" for strings).  If FSTRING contains more
specifiers than there are OBJ arguments, the part of FSTRING
beginning with the first specifier with no OBJ is ignored.
The OBJ may be scalar or arrays, but the dimensions of every OBJ
must be identical.  If the OBJ are arrays, Yorick behaves as
if the read were called in a loop numberof(OBJ1) times, filling
one array element of each of the OBJ according to FSTRING on
each pass through the loop.  (Note that this behavior includes
the case of reading columns of numbers by a single call to read.)
The return value N is the total number of scalar assignments
which were made as a result of this call.  (If there were 4
OBJ arguments, and each was an array with 17 elements, a return
value of N==35 would mean the following:  The first 8 elements
of OBJ1, OBJ2, OBJ3, and OBJ4 were read, and the 9th element of
elements of the OBJ which were not read to zero -- hence,
independent of the returned N, the all of the old data in the
OBJ arguments is overwritten.
(1) all elements of all OBJ have been filled, or (2) end-of-file
(or end of SOURCE for sread) is reached ("input failure"), or
(3) part of FSTRING or a conversion specifier supplied by
default fails to match the source text ("matching failure").
The FSTRING is composed of a series of "directives" which are
(1) whitespace -- means to skip any amount of whitespace in the
source text
(2) characters other than whitespace and % -- must match the
characters in the source text exactly, or matching failure
occurs and the read operation stops
(3) conversion specifiers beginning with % and ending with a
character specifying the type of conversion -- optionally
skip whitespace, then convert as many characters as
continue to "look like" the conversion type, possibly
producing a matching failure
The conversion specifier is of the form %*WSC, where:
is either the character '*' or not present
A specifier beginning with %* does not correspond to any of
the OBJ; the converted value will be discarded.
W is either a positive decimal integer specifying the maximum
field width (not including any skipped leading whitespace),
or not present if any number of characters up to end-of-line
is acceptable.
S is either one of the characters 'h', 'l', or 'L', or not
present.  Yorick allows this for compatibility with the C
library functions, but ignores it.
C is a character specifying the type of conversion:
d   - decimal integer
o   - octal integer
u   - unsigned decimal integer (same as d for Yorick)
x, X            - hex integer
e, f, g, E, G   - floating point real
s   - string of non-whitespace characters
[xxx]   - (xxx is any sequence of characters) longest string
of characters matching those in the list
[^xxx]  - longest string of characters NOT matching those in
the list (this is how you can extend %s to be
delimited by something other than whitespace)
%   - the ordinary % character; complete conversion
specification must be "%%"
The read function is modeled on the ANSI standard C library
fscanf and sscanf functions, but differs in several respects:
(1) Yorick's read cannot handle the %c, %p, or %n conversion
specifiers in FSTRING.
(2) Yorick's read never results in a portion of a line
being read -- any unused part of a line is simply discarded
(end FSTRING with "%[^\n]" if you want to save the trailing
part of an input line).
(3) As a side effect of (2), there are some differences between
fscanf and Yorick's read in how whitespace extending across
newlines is handled.
Builtin function, documented at i0/std.i   line 1994

```

```

raw routine to set the binary data structure of FILE according
to the text description in the Contents Log file CLOG_NAME.
Builtin function, documented at i0/std.i   line 2649

```

```
read_n, f, n0, n1, n2, ...

grabs the next numbers N0, N1, N2, ... from file F, skipping over
any whitespace, comma, semicolon, or colon delimited tokens which
are not numbers.  (Actually, only the first and last characters of
the token have to look like a number -- 4xxx3 would be read as 4.)
***WARNING*** at most ten Ns are allowed
The Ns can be arrays, provided all have the same dimensions.
Keyword,  defined at i0/std.i   line 2133

```

recover_file
```
recover_file, filename
or recover_file, filename, clogfile

writes the descriptive information at the end of a corrupted
binary file FILENAME from its Contents Log file CLOGFILE, which
is FILENAME+"L" by default.
Interpreted function, defined at i0/std.i   line 2655

```

reform
```
reform(x, dimlist)

returns array X reshaped according to dimension list DIMLIST.
Interpreted function, defined at i0/std.i   line 301

```

remove
```
remove

Builtin function, documented at i0/std.i   line 1986

```
SEE rename

rename
```
rename, old_filename, new_filename
remove filename

rename or remove a file.
Builtin function, documented at i0/std.i   line 1986

```

require
```
require

Builtin function, documented at i0/std.i   line 2254

```
SEE include

reshape
```
or reshape, reference, type, dimension_list
or reshape, reference

The REFERENCE must be an unadorned variable, not an expression;
reshape sets this variable to an LValue at the specified ADDRESS
with the specified TYPE and DIMENSION_LIST.  (See the array
function documentation for acceptable DIMENSION_LIST formats.)
If ADDRESS is an integer (e.g.- a long), the programmer is
responsible for assuring that the data at ADDRESS is valid.
If ADDRESS is a (Yorick) pointer, Yorick will assure that the
data pointed to will not be discarded, and the reshape will
fail if TYPE and DIMENSION_LIST extend beyond the pointee
bounds.  In the second form, ADDRESS is taken to be &REFERENCE;
that is, the TYPE and DIMENSION_LIST of the variable are changed
without doing any type conversion.  In the third form, REFERENCE
is set to nil ([]).  (Simple redefinition will not work on a
variable defined using reshape.)
WARNING: There are almost no situations for which reshape is
the correct operation.  Use reform instead.
Builtin function, documented at i0/std.i   line 278

```

restore
```
restore

Builtin function, documented at i0/std.i   line 3080

```
SEE save

rmdir
```
rmdir

Builtin function, documented at i0/std.i   line 2478

```
SEE mkdir