Re: [R] Google style
Duncan Murdoch murd...@stats.uwo.ca
on Tue, 01 Sep 2009 08:02:57 -0400 writes:
On 9/1/2009 6:37 AM, (Ted Harding) wrote:
On 01-Sep-09 10:25:53, Duncan Murdoch wrote:
Jim Lemon wrote:
Duncan Murdoch wrote:
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu
wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have
been good too.
Something I have thought myself.
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste
a lot of time some day, when you stare and stare at code like Terry's
and can't figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of
your brain made you type it that way and reads it as one statement in
the body, not two.
This is getting interesting. One habit I have developed in R to
emphasize a line continuation is to always write the above as:
zed-function(x,y,z) {
x+y+
z
}
That's a good habit. An alternative is to put parentheses around the
expression:
(x + y
+ z)
will work.
The trailing operator signalling to me and the interpreter that
there's more to come. A semicolon after the z would be innocuous.
Now I know that this marks me as a crabby old fart who learned
to program on Hollerith cards where there had to be firm
conventions on when a line of code ended. Still, given the moiety
of global warming attributable to endless discussions about how
many spaces should be used for indentation, I think the use of
the semicolon as a personal aid to interpretation is at worst a
harmless affectation.
I think it's worse. To me, it's like putting in a comment that is
wrong, or writing code like this:
one - 2
x - x + one
Code has meaning, it's not just a bunch of binary instructions to the
computer. If the meaning and the look of the code clash, it is going
to lead to problems.
Duncan Murdoch
And surely that is precisely the point of Jim's use of ;!
It is, in effect, ignored by R; but to Jim it means This marks the
end of a command. Surely useful, and surely not in the same league
as a comment that is wrong. You may see it as noise, but then
you can filter it out.
I think you're missing the point. Using C-like syntax in R is
misleading because you will think it has C-like meaning. You will read
x + y
+ z;
as one statement, not two. (Actually you could argue that in R there are
three statements there, but the third one is empty).
This is harmful in the same way using misleading variable names is
harmful: as long as you're paying attention you'll get it right, but
when you are working on a hard problem and can't devote enough neurons
to this particular task, you'll get it wrong, and have a hard-to-spot
bug in your code. You'll decide you need to split a statement across
two lines, and write it in C style like the statements above, instead of
in correct R syntax.
Duncan Murdoch
I very strongly agree with Duncan on his very points.
In addition, note that the extra noise (horrible end line ';')
not only adds to the global warming ;-) but also slightly slows
the parsing and hence total execution time of your code ...
even more global warming ...
Martin Maechler
As one COF to another, I have to say that Jim's posting took me
back to the early days of my own evolution. That was dandy!
(Dinosaurs are not dead yet).
Ted.
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Re: [R] Google style
Duncan Murdoch wrote:
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu
wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have been
good too.
Something I have thought myself.
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste
a lot of time some day, when you stare and stare at code like Terry's
and can't figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of
your brain made you type it that way and reads it as one statement in
the body, not two.
This is getting interesting. One habit I have developed in R to
emphasize a line continuation is to always write the above as:
zed-function(x,y,z) {
x+y+
z
}
The trailing operator signalling to me and the interpreter that there's
more to come. A semicolon after the z would be innocuous. Now I know
that this marks me as a crabby old fart who learned to program on
Hollerith cards where there had to be firm conventions on when a line of
code ended. Still, given the moiety of global warming attributable to
endless discussions about how many spaces should be used for
indentation, I think the use of the semicolon as a personal aid to
interpretation is at worst a harmless affectation.
Jim
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Google style
Jim Lemon wrote:
Duncan Murdoch wrote:
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu
wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have been
good too.
Something I have thought myself.
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste
a lot of time some day, when you stare and stare at code like Terry's
and can't figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of
your brain made you type it that way and reads it as one statement in
the body, not two.
This is getting interesting. One habit I have developed in R to
emphasize a line continuation is to always write the above as:
zed-function(x,y,z) {
x+y+
z
}
That's a good habit. An alternative is to put parentheses around the
expression:
(x + y
+ z)
will work.
The trailing operator signalling to me and the interpreter that there's
more to come. A semicolon after the z would be innocuous. Now I know
that this marks me as a crabby old fart who learned to program on
Hollerith cards where there had to be firm conventions on when a line of
code ended. Still, given the moiety of global warming attributable to
endless discussions about how many spaces should be used for
indentation, I think the use of the semicolon as a personal aid to
interpretation is at worst a harmless affectation.
I think it's worse. To me, it's like putting in a comment that is
wrong, or writing code like this:
one - 2
x - x + one
Code has meaning, it's not just a bunch of binary instructions to the
computer. If the meaning and the look of the code clash, it is going to
lead to problems.
Duncan Murdoch
Jim
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Google style
On 01-Sep-09 10:25:53, Duncan Murdoch wrote:
Jim Lemon wrote:
Duncan Murdoch wrote:
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu
wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have
been good too.
Something I have thought myself.
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste
a lot of time some day, when you stare and stare at code like Terry's
and can't figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of
your brain made you type it that way and reads it as one statement in
the body, not two.
This is getting interesting. One habit I have developed in R to
emphasize a line continuation is to always write the above as:
zed-function(x,y,z) {
x+y+
z
}
That's a good habit. An alternative is to put parentheses around the
expression:
(x + y
+ z)
will work.
The trailing operator signalling to me and the interpreter that
there's more to come. A semicolon after the z would be innocuous.
Now I know that this marks me as a crabby old fart who learned
to program on Hollerith cards where there had to be firm
conventions on when a line of code ended. Still, given the moiety
of global warming attributable to endless discussions about how
many spaces should be used for indentation, I think the use of
the semicolon as a personal aid to interpretation is at worst a
harmless affectation.
I think it's worse. To me, it's like putting in a comment that is
wrong, or writing code like this:
one - 2
x - x + one
Code has meaning, it's not just a bunch of binary instructions to the
computer. If the meaning and the look of the code clash, it is going
to lead to problems.
Duncan Murdoch
And surely that is precisely the point of Jim's use of ;!
It is, in effect, ignored by R; but to Jim it means This marks the
end of a command. Surely useful, and surely not in the same league
as a comment that is wrong. You may see it as noise, but then
you can filter it out.
As one COF to another, I have to say that Jim's posting took me
back to the early days of my own evolution. That was dandy!
(Dinosaurs are not dead yet).
Ted.
E-Mail: (Ted Harding) ted.hard...@manchester.ac.uk
Fax-to-email: +44 (0)870 094 0861
Date: 01-Sep-09 Time: 11:37:52
-- XFMail --
__
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Google style
On 9/1/2009 6:37 AM, (Ted Harding) wrote:
On 01-Sep-09 10:25:53, Duncan Murdoch wrote:
Jim Lemon wrote:
Duncan Murdoch wrote:
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu
wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have
been good too.
Something I have thought myself.
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste
a lot of time some day, when you stare and stare at code like Terry's
and can't figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of
your brain made you type it that way and reads it as one statement in
the body, not two.
This is getting interesting. One habit I have developed in R to
emphasize a line continuation is to always write the above as:
zed-function(x,y,z) {
x+y+
z
}
That's a good habit. An alternative is to put parentheses around the
expression:
(x + y
+ z)
will work.
The trailing operator signalling to me and the interpreter that
there's more to come. A semicolon after the z would be innocuous.
Now I know that this marks me as a crabby old fart who learned
to program on Hollerith cards where there had to be firm
conventions on when a line of code ended. Still, given the moiety
of global warming attributable to endless discussions about how
many spaces should be used for indentation, I think the use of
the semicolon as a personal aid to interpretation is at worst a
harmless affectation.
I think it's worse. To me, it's like putting in a comment that is
wrong, or writing code like this:
one - 2
x - x + one
Code has meaning, it's not just a bunch of binary instructions to the
computer. If the meaning and the look of the code clash, it is going
to lead to problems.
Duncan Murdoch
And surely that is precisely the point of Jim's use of ;!
It is, in effect, ignored by R; but to Jim it means This marks the
end of a command. Surely useful, and surely not in the same league
as a comment that is wrong. You may see it as noise, but then
you can filter it out.
I think you're missing the point. Using C-like syntax in R is
misleading because you will think it has C-like meaning. You will read
x + y
+ z;
as one statement, not two. (Actually you could argue that in R there are
three statements there, but the third one is empty).
This is harmful in the same way using misleading variable names is
harmful: as long as you're paying attention you'll get it right, but
when you are working on a hard problem and can't devote enough neurons
to this particular task, you'll get it wrong, and have a hard-to-spot
bug in your code. You'll decide you need to split a statement across
two lines, and write it in C style like the statements above, instead of
in correct R syntax.
Duncan Murdoch
As one COF to another, I have to say that Jim's posting took me
back to the early days of my own evolution. That was dandy!
(Dinosaurs are not dead yet).
Ted.
E-Mail: (Ted Harding) ted.hard...@manchester.ac.uk
Fax-to-email: +44 (0)870 094 0861
Date: 01-Sep-09 Time: 11:37:52
-- XFMail --
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and provide commented, minimal, self-contained, reproducible code.
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: [R] Google style
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu wrote: SNIP The authors borrowed so much else from C, the semicolon would have been good too. SNIP I know real R coders will chuckle but I've taken to using semicolons just because it looks better to my eyes and let's my brain know where I think lines end. True, the language isn't checking for them but it keeps my typing consistent with the only other language I program in. (EasyLanguage) plot(cumsum(T1$PL_SUM) ~ T1$MyDate, typ=l); lines(cumsum(Z1$PL_SUM) ~ Z1$MyDate, typ=l, col=green); lines(cumsum(Z2$PL_SUM) ~ Z2$MyDate, typ=l, col=red); lines(cumsum(Z3$PL_SUM) ~ Z3$MyDate, typ=l, col=purple); While it's not supported today, maybe one day there could be a way it was? Who knows... Cheers, Mark __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Google style
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have been
good too.
SNIP
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste a
lot of time some day, when you stare and stare at code like Terry's and
can't figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of
your brain made you type it that way and reads it as one statement in
the body, not two.
Duncan Murdoch
but I've taken to using semicolons
just because it looks better to my eyes and let's my brain know where
I think lines end. True, the language isn't checking for them but it
keeps my typing consistent with the only other language I program in.
(EasyLanguage)
plot(cumsum(T1$PL_SUM) ~ T1$MyDate, typ=l);
lines(cumsum(Z1$PL_SUM) ~ Z1$MyDate, typ=l, col=green);
lines(cumsum(Z2$PL_SUM) ~ Z2$MyDate, typ=l, col=red);
lines(cumsum(Z3$PL_SUM) ~ Z3$MyDate, typ=l, col=purple);
While it's not supported today, maybe one day there could be a way it
was? Who knows...
Cheers,
Mark
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Re: [R] Google style
This is where a good editor with proper syntactic indentation is helpful.
The first example is Terry's function as indented by ESS. It is very
clear that there are two lines with parallel indentation.
zed - function(x,y,z) {
x + y
+z;
}
The second function is modified to place the + on the first
line as the indicator of continuation. The second line is indented
by ESS to show that it is a continuation line.
zedc - function(x,y,z) {
x + y +
z;
}
Rich
[[alternative HTML version deleted]]
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Re: [R] Google style
On Mon, Aug 31, 2009 at 10:00 AM, Duncan Murdochmurd...@stats.uwo.ca wrote:
On 8/31/2009 11:50 AM, Mark Knecht wrote:
On Mon, Aug 31, 2009 at 6:36 AM, Terry Therneauthern...@mayo.edu wrote:
SNIP
The authors borrowed so much else from C, the semicolon would have been
good too.
SNIP
I know real R coders will chuckle
I'd say cringe, rather than chuckle. This is going to make you waste a lot
of time some day, when you stare and stare at code like Terry's and can't
figure out what's wrong with it:
zed - function(x,y,z) {
x + y
+z;
}
The value of the function is +z, not x+y+z, even though the C part of your
brain made you type it that way and reads it as one statement in the body,
not two.
Duncan Murdoch
Oh, I completely agree.
Nominally I would have broken my rules for inserting semi-colons as
shown above. I should have done something more like this:
zed - function(x,y,z) {
x + y;
+z;
}
;
but your point is completely correct. If I start forgetting that the
semi-colon is doing nothing then I'll cause myself problems. Also, if
I hot some case where the semi-colon serves a real purpose in R I'll
be totally confused, so this isn't a good thing to be doing. Not sure
I'll continue, but as I learn the language it's helped me see where
code lines end a bit better.
Thanks,
Mark
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