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Re: st: number of dates in x axis
From
Maria Ana Vitorino <[email protected]>
To
<[email protected]>
Subject
Re: st: number of dates in x axis
Date
Wed, 25 May 2011 15:21:37 -0400
Thanks Nick.
Your suggestions worked well and were very helpful (as always...).
Ana
On May 25, 2011, at 3:45 AM, Nick Cox wrote:
Thanks for the details.
By re-running bits of your code you are adding elements again and
again to the local -mydates-. It's like a bag and you keep putting
things into it. You would need to empty the bag first, by
local mydates
However, that turns to be unnecessary for other reasons.
You are declaring these dates to be monthly, but from the values they
can only be daily dates, as explained in my previous post. The fact
that they are spaced monthly is separate. Look again at the result of
your -xtset-: -xtset- is interpreting your data as months in the years
3459 to 3519, about which all that is written is as yet science
fiction.
. xtset person date1, monthly
panel variable: person (unbalanced)
time variable: date1, 3459m1 to 3519m11, but with gaps
delta: 1 month
Also, all this code does is ask for dates within 2009.
. forval i = 4(2)11 {
2. local thisdate = mdy(`i', 1, 2009)
3. local mydates `mydates' `thisdate'
4. }
However, the good news is that your data, evidently recorded once a
month, can be recast, at least for graphical purposes, as monthly
data.
gen month = mofd(date1)
xtset person month, monthly
su month, meanonly
xtline calories, overlay xlabel(`r(min)'(2)`r(max)', format(%tm_m_Y)
ang(v))
That also gives an answer to your earlier question about automating
the calculation of the limits. -summarize- leaves in its wake r(min)
and r(max) and you feed their local macro personas to -xtline-. You
can of course tweak the format to some other %tm format.
The fact that you have monthly-spaced daily dates can now be seen as
tacit in your first post, but I didn't pick that up. I saw only values
like 17988 which were familiar as recent daily dates.
Nick
On Tue, May 24, 2011 at 8:34 PM, Maria Ana Vitorino
<[email protected]> wrote:
Hi Nick,
I really appreciate your help and patience.
Here is the code and some descriptives that may help to find the
bug...
Thanks so much,
Ana
generate date1=date(date,"MY")
format date1 %tm
list date1 date in 1
+------------------+
| date1 date |
|------------------|
1. | 3469m3 Aug2009 |
+------------------+
. egen newvar = axis(date1), label(date)
. tab newvar
date1 | Freq. Percent Cum.
------------+-----------------------------------
Apr2009 | 119 4.38 4.38
Aug2009 | 130 4.78 9.15
Sep2009 | 126 4.63 13.79
Oct2009 | 126 4.63 18.42
Nov2009 | 134 4.93 23.35
Dec2009 | 151 5.55 28.90
Jan2010 | 153 5.62 34.52
Feb2010 | 150 5.51 40.04
Mar2010 | 150 5.51 45.55
Apr2010 | 149 5.48 51.03
May2010 | 146 5.37 56.40
Jul2010 | 153 5.62 62.02
Aug2010 | 151 5.55 67.57
Sep2010 | 153 5.62 73.20
Oct2010 | 153 5.62 78.82
Dec2010 | 161 5.92 84.74
Feb2011 | 142 5.22 89.96
Mar2011 | 154 5.66 95.62
Apr2011 | 119 4.38 100.00
------------+-----------------------------------
Total | 2,720 100.00
. sum date1
Variable | Obs Mean Std. Dev. Min Max
-------------
+--------------------------------------------------------
date1 | 2720 18380.68 198.1158 17988 18718
. xtset person date1, monthly
panel variable: person (unbalanced)
time variable: date1, 3459m1 to 3519m11, but with gaps
delta: 1 month
. forval i = 4(2)11 {
2. local thisdate = mdy(`i', 1, 2009)
3. local mydates `mydates' `thisdate'
4. }
.
. display `thisdate'
18171
. display `mydates'
17988180491811018171
.
.
. local thisdate = mdy(4,1,2011)
. local mydates `mydates' `thisdate'
.
. display `thisdate'
18718
. display `mydates'
1798818049181101817118718
. xtline calories, overlay xlabel(`mydates', format(%d_m_Y) ang(v))
invalid label specifier, : 15341 15400 15461 15522 15584 15645
15645 17901
17960 18021 18082 18144 1820
5 17988 18049 18110 18171 18232 . . . . 18718 15341 15400 15461
15522
15584 15645 15706 15341 15400 15
461 15522 15584 15645 15706 17988 18049 18110 18171 18718 18718
18628
18628 18628 17898 17957 18018 18
079 18141 18628 18628:
r(198);
On May 24, 2011, at 3:05 PM, Nick Cox wrote:
You are burdening me with questions that I can't answer! You are not
showing me the code that fails. Also, you are guessing again.
But it seems that you have daily dates.
Applying a %tm format to daily dates is legal but pointless. It
gives you
a result that does not apply to your dates.
The number 18110 is
(D) 1 August 2009 as a daily date
_but_
(M) March 3469 as a monthly date, i.e. a date almost 1460 years
into the
future. That's what
But that is not going to fail.
In my first post I gave an example of a format for daily dates
that shows
month and year: %d_m_Y.
I am going to try a third and last time. If you show me the code
that
fails, I will try to tell you your mistake. Otherwise what you
don't tell us
remains inscrutable.
Nick
[email protected]
Maria Ana Vitorino
Thanks. My code is a little more complicated than the example so I
didn't want to burden you with it. But I understand your position.
I think the issue has to do with the formatting of the date
variable...I can't seem to get it to work.
This is what I'm getting:
. generate date1=date(date,"MY")
. format date1 %tm
. list date1 date in 1
+------------------+
| date1 date |
|------------------|
1. | 3469m3 Aug2009 |
+------------------+
What am I doing wrong?
Thanks,
Ana
On May 24, 2011, at 2:18 PM, Nick Cox wrote:
% sacrificial line.
Nick
[email protected]
-----Original Message-----
From: Nick Cox
Sent: 24 May 2011 19:16
To: '[email protected]'
Subject: RE: st: number of dates in x axis
Please: I want to see the _exact_ code you typed. No commentary, no
paraphrase, no speculation. If you want to debug your code
yourself,
feel free to do so. If you want me to try to debug your code, I am
happy to try, but that means your code, not your thoughts about
what
might be wrong with your code.
Nick
[email protected]
-----Original Message-----
From: [email protected]
[mailto:[email protected]
] On Behalf Of Maria Ana Vitorino
Sent: 24 May 2011 19:11
To: [email protected]
Subject: Re: st: number of dates in x axis
I tried your code again (this time by pasting it into the do-file
editor instead into the command window) and it worked. But my
version
is not working (I still get the invalid label specifier message).
Could it be because my time variable has gaps? Also, how can one
setup
the "11" in your for loop without having to make mental
calculations
regarding the number of months?
Thanks for the help!
Ana
On May 24, 2011, at 1:31 PM, Nick Cox wrote:
Yes. Show me the _exact_ code you typed.
Nick
[email protected]
-----Original Message-----
From: [email protected]
[mailto:[email protected]
] On Behalf Of Maria Ana Vitorino
Sent: 24 May 2011 18:29
To: [email protected]
Subject: Re: st: number of dates in x axis
Thanks Nick.
I tried running your example but I got the error message "invalid
label specifier, : 15341 15400 15461 ..."
Any suggestions?
Thanks!
Ana
On May 24, 2011, at 4:20 AM, Nick Cox wrote:
There is relevant material at
Stata 7: How can I get "nice" date labels on a graph?
http://www.stata.com/support/faqs/graphics/nicedate.html
StataCorp have added this annotation:
"Note: This FAQ is relevant for users of releases prior to
Stata 8.
For Stata 8 see update from 12 September 2003."
In fact the techniques there do remain useful for some problems.
Here's an example with different data. Here I decide that I want
labels every 2 months from 1 January 2002 to 1 January 2003. I
loop
over the dates and put them in a bag, namely a local macro.
sysuse xtline1
xtset person day
forval i = 1(2)11 {
local thisdate = mdy(`i', 1, 2002)
local mydates `mydates' `thisdate'
}
local thisdate = mdy(1,1,2003)
local mydates `mydates' `thisdate'
xtline calories, overlay xlabel(`mydates', format(%d_m_Y) ang(v))
See also
SJ-7-4 gr0030 . Stata tip 55: Better axis labeling for time
points/
intervals
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
N. J. Cox
Q4/07 SJ 7(4):590--592 (no
commands)
tip on labeling graphs for time points and time intervals
On Tue, May 24, 2011 at 4:45 AM, Maria Ana Vitorino
<[email protected]> wrote:
I have the following data:
+------------------------+
| Person Weight Date |
|------------------------|
1. | Name1 50 17988 |
2. | Name1 55 18110 |
3. | Name1 50 18141 |
4. | Name1 45 18171 |
5. | ... . . |
|------------------------|
6. | Name2 85 18110 |
7. | Name2 88 18171 |
8. | Name3 68 17988 |
9. | ... . . |
10. | .. . . |
|------------------------|
11. | NameN . . |
+------------------------+
The labels for the date variables are the months' names (plus
year)
(e.g.
"jan2006", "feb2007", etc)
If I do something like:
xtline Weight , overlay i(Person) t(Date) xlab(, valuelabel)
The month names show up on the xaxis BUT only every 6 months
or so.
How can
I control the number of "ticks" (AND month names ) that show
up on
the
x-axis? (suppose I want a tick every 2 months or even every
month)
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