Question about "#"

[jasong]

Normally, I would do a web or forum search, but in this case I don't know what I could possibly enter, so I'm coming to you guys:

When you see # what does it mean?

[Uncwilly]

It has a variety of meanings, including the two most common and a math special:

1) Number, as in phone#, car #54, Apartment #13
2) Pound, 25# of nails, 76# of trombones
3) Primordial, like factorial (1), but only the primes are used,
17# = 2*3*5*7*11*13*17

[sdbardwick]

Originally Posted by Uncwilly

It has a variety of meanings, including the two most common and a math special:

1) Number, as in phone#, car #54, Apartment #13
2) Pound, 25# of nails, 76# of trombones
3) Primordial, like factorial (1), but only the primes are used,
17# = 2*3*5*7*11*13*17

I think uncwilly meant (darn typos):

"3) Primordial, like factorial (!), but only the primes are used,
17# = 2*3*5*7*11*13*17"

"#" in musical notation is the sharp sign; B# = B sharp

[gribozavr]

And it has at least one computer-special meaning -- comment. In some file, processed with a program (for exmaple, .n and .poly files in ggnfs, most u*ix config files etc) # usually means that everything following the # symbol till the end of line is ignored by the program. For example (.poly file) (all comments are in bold):

# this is a .poly file!
name: 9413_41_minus_C115
n:  351...777 # the whole composite here
m:  681285025000323251793
deg: 5
c5: 23915641680
c4: -11320278741849
c3: -13573165856179426
c2: 5247009001133649662
c1: 264089278408810837366
c0: -28400210612086968847208
skew: 125.910
type: gnfs
# adj. I(F,S) = 52.516
# E(F1,F2) = 5.783303e-05
# GGNFS version 0.71.4 polyselect.
# Options were:
# lcd=1, enumLCD=720, maxS1=59.00000000, seed=1117052222.
# maxskew=2000.0
# These parameters should be manually set:
rlim: 4500000
alim: 2250000
lpbr: 27
lpba: 27
mfbr: 50
mfba: 50
rlambda: 2.4
alambda: 2.4
q0: 4500000
qintsize: 60000

[lycorn]

In the C/C++ languages (and also Clipper), the # indicates preprocessor directives (e.g. #include <iostream>).

[xilman]

As an emoticon, :-# is generally taken to mean that the person concerned has a beard. In my case, I ought to use 8-# or B-# as I have both spectacles and a beard, but I generally use 8-) or 8-(

There are, of course, many other uses for the # character. Incidentally, the pound usage (as in pounds weight, not pounds sterling) is largely confined to North America. The British never use it, always lb.

Paul

[jasong]

I guess I should have been more specific.

The primorial definition is the one I needed, btw.

[xilman]

Originally Posted by jasong

I guess I should have been more specific.

The primorial definition is the one I needed, btw.

You should always be very careful about what you ask for, in case you receive it.

Paul

[Uncwilly]

Originally Posted by xilman

Incidentally, the pound usage (as in pounds weight, not pounds sterling) is largely confined to North America. The British never use it, always lb.

And generally hand written, more so than typed.
Also it is the basis for a game that is a kid's game that Hollywood co-op'ed and misnomered into squares.

[Peter Nelson]

As Paul pointed out, we Brits use lb or lbs (plural) for pounds weight (although European laws now say that for instance food must be labelled and sold in metric Kilograms rather than imperial measurements!)

Additionally, 'pound' (aka pounds sterling) is our currency for which we use the symbol £ for currency (for clarity GBP).

We call the # symbol "hash" if we know what it is. We never call it "pound".

As for music I have studied music theory, and depending on key, B sharp can exist, although it is equivalent to the note most people would call "C". C sharp (the black note just right of C) would have been a better example to illustrate that # denotes a note one semitone higher in pitch. But that's also the name of a programming language.

The use of # to mean "number" is quite American and would probably not be known to half the UK population, however, I like it and use it. Globalisation is spreading this usage as more people now read documents authored in the USA.

I think this is a little like the use of "." versus "," for the decimal separator.

I find it very annoying (not to say confusing) the way that some countries like France use "," in for example their prices and other numbers instead of the "." (period/decimal point) symbol.

I might write 23.99 whereas the French write 23,99

To me "," can (optionally) be used to group blocks of 3 digits for ease of reading eg "23,444,895.55"

Using the comma is also potentially confusing as it is also used to distinguish elements in a sequence eg. 2,3,5,6,11,13

Reasons for the different usage are probably historic, but I think the European Union's standardisation attempts would be more usefully directed to address this non-uniformity within Europe so that everybody could standardise on use of "." rather than "," as the decimal point separator.

While they are doing this they could add "#" to our European vocabulary too.

P.S. Following on from some of the posts above re computer languages, I will add that in the BASIC language "#" is used to signify a file handle for I/O as opposed to the default input and output devices of screen and keyboard.

eg
OPEN "datafile.txt" FOR INPUT AS #2
WHILE NOT EOF(2)
INPUT #2, A$
PRINT A$ : ' display it on the screen
WEND
CLOSE #2

[Peter Nelson]

Originally Posted by Uncwilly

And generally hand written, more so than typed.
Also it is the basis for a game that is a kid's game that Hollywood co-op'ed and misnomered into squares.

As a game, the ones I know are it is either:

the game grid drawn for "naughts and crosses" prior to making any moves.

OR

the grid typically chalked in white on a hard path for children to play the skipping game "hopskotch" which involves standing/jumping into the gaps with one or both feet without touching any of the lines of the grid.