I have a data set that allows linking friends (i.e. observing peer groups) and thereby one can observe the characteristics of an individual's friends. What I have is an 8 digit identifier, id, each id's friend id's (up to 10 friends), and then many characteristic variables.
I want to take an individual and create a variables that are the foreign born status of each friend.
I already have an indicator for each person that is 1 if foreign born. Below is a small example, for just one friend. Notice, MF1 means male friend 1 and then MF1id is the id number for male friend 1. The respondents could list up to 5 male friends and 5 female friends.
So, I need Stata to look at MF1id and then match it down the id column, then look over to f_born for that matched id, and finally input the value of f_born there back up to the original id under MF1f_born.
edit: I did a poor job of explaining the data structure. I have a cross section so 1 observation per unique id. Row 1 is the first 8 digit id number with all the variables following over the row. The repeating id numbers are between the friend id's listed for each person (mf1id for example) and the id column. I hope that is a bit more clear.
Kevin Crow wrote vlookup that makes this sort of thing pretty easy:
use http://www.ats.ucla.edu/stat/stata/faq/dyads, clear
drop team y
rename (rater ratee) (id mf1_id)
bys id: gen f_born = mod(id,2)==1
net install vlookup
vlookup mf1_id, gen(mf1f_born) key(id) value(f_born)
So, Dimitriy's suggestion of vlookup is perfect except it will not work for me. After trying vlookup with both my data set, the UCLA data that Dimitriy used for his example, and a toy data set I created vlookup always failed at the point the program attempts to save a temp file to my temp folder. Below is the program for vlookup. Notice its sets tempfile file, manipulates the data, and then saves the file.
*! version 1.0.0 KHC 16oct2003
program define vlookup, sortpreserve
version 8.0
syntax varname, Generate(name) Key(varname) Value(varname)
qui {
tempvar g k
egen `k' = group(`key')
egen `g' = group(`key' `value')
local k = `k'[_N]
local g = `g'[_N]
if `k' != `g' {
di in red "`value' is unique within `key';"
di in red /*
*/ "there are multiple observations with different `value'" /*
*/ " within `key'."
exit 9
}
preserve
tempvar g _merge
tempfile file
sort `key'
by `key' : keep if _n == 1
keep `key' `value'
sort `key'
rename `key' `varlist'
rename `value' `generate'
save `file', replace
restore
sort `varlist'
joinby `varlist' using `file', unmatched(master) _merge(`_merge')
drop `_merge'
}
end
exit
For some reason, Stata gave me an error, "invalid file," at the save `file', replace point. I have a restricted data set with requirments to point all my Stata temp files to a very specific folder that has an erasure program sweeping it every so often. I don't know why this would create a problem but maybe it is, I really don't know. Regardless, I tweaked the vlookup program and it appears to do what I need now.
clear all
set more off
capture log close
input aid mf1aid fborn
1 2 1
2 1 1
3 5 0
4 2 0
5 1 0
6 4 0
7 6 1
8 2 .
9 1 0
10 8 1
end
program define justlinkit, sortpreserve
syntax varname, Generate(name) Key(varname) Value(name)
qui {
preserve
tempvar g _merge
sort `key'
by `key' : keep if _n ==1
keep `key' `value'
sort `key'
rename `key' `varlist'
rename `value' `generate'
save "Z:\Jonathan\created data sets\justlinkit program\fchara.dta",replace
restore
sort `varlist'
joinby `varlist' using "Z:\Jonathan\created data sets\justlinkit program\fchara.dta", unmatched(master) _merge(`_merge')
drop `_merge'
}
end
// set trace on
justlinkit mf1aid, gen(mf1_fborn) key(aid) value(fborn)
sort aid
list
Well, this fixed my problem. Thanks to all who responded I would not have figured this out without you.
Related
i am trying to read a csv file and my code is as follows
param=csvRead("C:\Users\USER\Dropbox\VOA-BK code\assets\Iris.csv",",","%i",'double',[],[],[1 2 3 4]); //reads number of clusters and features
data=csvRead("C:\Users\USER\Dropbox\VOA-BK code\assets\Iris.csv",",","%f",'double',[],[],[3 1 19 4]); //reads the values
numft=param(1,1);//save number of features
numcl=param(2,1);//save number of clusters
data_pts=0;
data_pts = max(size(data, "r"));//checks how many number of rows
disp(data(numft-3:data_pts,:));//print all data points (I added -3 otherwise it displays only 15 rows)
disp(numft);//print features
disp(data_pts);//print features
disp(param);
endfunction
below is the values that i am trying to read
features,4,,
clusters,3,,
5.1,3.5,1.4,0.2
4.9,3,1.4,0.2
4.7,3.2,1.3,0.2
4.6,3.1,1.5,0.2
5,3.6,1.4,0.2
7,3.2,4.7,1.4
6.4,3.2,4.5,1.5
6.9,3.1,4.9,1.5
5.5,2.3,4,1.3
6.5,2.8,4.6,1.5
5.7,2.8,4.5,1.3
6.3,3.3,6,2.5
5.8,2.7,5.1,1.9
7.1,3,5.9,2.1
6.3,2.9,5.6,1.8
6.5,3,5.8,2.2
7.6,3,6.6,2.1
I do not know why the code only displays 15 rows instead of 17. The only time it displays the correct matrix is when i put -3 in numft but with that, the number of columns would be 1. I am so confused. Is there a better way to read the values?
In the csvRead call in the first line of your script the boundaries of the region to read is incorrect, it should be corrected like this:
param=csvRead("C:\Users\USER\Dropbox\VOA-BK code\assets\Iris.csv",",","%i",'double',[],[],[1 2 2 2]);
I was working through reshaping a file and was wondering how Stata handled a file in the below format. Using data from a race, for example.
Race_Number Race_Date Racer_1_Name Racer_2_Name Racer_3_Name Racer_1_Position Racer_2_Position Racer_3_Position
Is it possible to transform this to the following.
Race_Number Race_Date Racer_Name Racer Position
Out of curiosity I created the above dataset and reshape did not work and I had to manually manipulate.
We appreciate you show us exactly what your input/output was. Things like
...reshape did not work and I had to manually manipulate.
don't tell us much.
Also, a complete toy data set would have helped. I assume you mean Race_Date where you typed Race Date (first code line) and Racer_Position where you typed Racer Position (second code line).
You can try
clear all
set more off
*----- example dataset -----
input ///
Race_Num Race_Dat str5(R1_Name R2_Name R3_Name) R1_Pos R2_Pos R3_Pos
1 5 "Al" "Bob" "Carl" 3 2 1
2 7 "Al" "Bob" "Carl" 3 1 2
3 15 "Al" "Bob" "Carl" 1 2 3
end
format Race_Dat %td
list
*----- what you want -----
forvalues i = 1/3 {
rename R`i'_Name Nam_R`i'
rename R`i'_Pos Pos_R`i'
}
list
reshape long Pos_R Nam_R, i(Race_Num) j(Racer)
order Race_Num Race_Dat
list, sepby(Race_Num)
All I did was change variable names before the reshape.
A better way is to use the # and then there's no need for renaming variables:
reshape long R#_Pos R#_Name, i(Race_Num) j(Racer)
I have 48 matrices of dimensions 1,000 rows and 300,000 columns where each column has a respective ID, and each row is a measurement at one time point. Each of the 48 matrices is of the same dimension and their column IDs are all the same.
The way I have the matrices stored now is as RData objects and also as text files. I guess for SQL I'd have to transpose and store by ID, and in such case now the matrix would be of dimensions 300,000 rows and 1,000 columns.
I guess if I transpose it a small version of the data would look like this:
id1 1.5 3.4 10 8.6 .... 10 (with 1,000 columns, and 30,0000 rows now)
I want to store them in a way such that I can use R to retrieve a few of the rows (~ 5 to 100 each time).
The general strategy I have in mind is as follows:
(1) Create a database in sqlite3 using R that I will use to store the matrices (in different tables)
For file 1 to 48 (each file is of dim 1,000 rows and 300,000 columns):
(2) Read in file into R
(3) Store the file as a matrix in R
(4) Transpose the matrix (now its of dimensions 300,000 rows and 1,000 columns). Each row now is the unique id in the table in sqlite.
(5) Dump/write the matrix into the sqlite3 database created in (1) (dump it into a new table probably?)
Steps 1-5 are to create the DB.
Next, I need step 6 to read-in the database:
(6) Read some rows (at most 100 or so at a time) into R as a (sub)matrix.
A simple example code doing steps 1-6 would be best.
Some Thoughts:
I have used SQL before but it was mostly to store tabular data where each column had a name, in this case each column is just one point of the data matrix, I guess I could just name it col1 ... to col1000? or there are better tricks?
If I look at: http://sandymuspratt.blogspot.com/2012/11/r-and-sqlite-part-1.html they show this example:
dbSendQuery(conn = db,
"CREATE TABLE School
(SchID INTEGER,
Location TEXT,
Authority TEXT,
SchSize TEXT)")
But in my case this would look like:
dbSendQuery(conn = db,
"CREATE TABLE mymatrixdata
(myid TEXT,
col1 float,
col2 float,
.... etc.....
col1000 float)")
I.e., I have to type in col1 to ... col1000 manually, that doesn't sound very smart. This is where I am mostly stuck. Some code snippet would help me.
Then, I need to dump the text files into the SQLite database? Again, unsure how to do this from R.
Seems I could do something like this:
setwd(<directory where to save the database>)
db <- dbConnect(SQLite(), dbname="myDBname")
mymatrix.df = read.table(<full name to my text file containing one of the matrices>)
mymatrix = as.matrix(mymatrix.df)
Here I need to now the coe on how to dump this into the database...
Finally,
How to fast retrieve the values (without having to read the entire matrices each time) for some of the rows (by ID) using R?
From the tutorial it'd look like this:
sqldf("SELECT id1,id2,id30 FROM mymatrixdata", dbname = "Test2.sqlite")
But it the id1,id2,id30 are hardcoded in the code and I need to dynamically obtain them. I.e., sometimes i may want id1, id2, id10, id100; and another time i may want id80, id90, id250000, etc.
Something like this would be more approp for my needs:
cols.i.want = c("id1","id2","id30")
sqldf("SELECT cols.i.want FROM mymatrixdata", dbname = "Test2.sqlite")
Again, unsure how to proceed here. Code snippets would also help.
A simple example would help me a lot here, no need to code the whole 48 files, etc. just a simple example would be great!
Note: I am using Linux server, SQlite 3 and R 2.13 (I could update it as well).
In the comments the poster explained that it is only necessary to retrieve specific rows, not columns:
library(RSQLite)
m <- matrix(1:24, 6, dimnames = list(LETTERS[1:6], NULL)) # test matrix
con <- dbConnect(SQLite()) # could add dbname= arg. Here use in-memory so not needed.
dbWriteTable(con, "m", as.data.frame(m)) # write
dbGetQuery(con, "create unique index mi on m(row_names)")
# retrieve submatrix back as m2
m2.df <- dbGetQuery(con, "select * from m where row_names in ('A', 'C')
order by row_names")
m2 <- as.matrix(m2.df[-1])
rownames(m2) <- m2.df$row_names
Note that relational databases are set based and the order that the rows are stored in is not guaranteed. We have used order by row_names to get out a specific order. If that is not good enough then add a column giving the row index: 1, 2, 3, ... .
REVISED based on comments.
There is an inconsistency with dataframes that I cant explain. In the following, I'm not looking for a workaround (already found one) but an explanation of what is going on under the hood and how it explains the output.
One of my colleagues which I talked into using python and pandas, has a dataframe "data" with 12,000 rows.
"data" has a column "length" that contains numbers from 0 to 20. she wants to divided the dateframe into groups by length range: 0 to 9 in group 1, 9 to 14 in group 2, 15 and more in group 3. her solution was to add another column, "group", and fill it with the appropriate values. she wrote the following code:
data['group'] = np.nan
mask = data['length'] < 10;
data['group'][mask] = 1;
mask2 = (data['length'] > 9) & (data['phraseLength'] < 15);
data['group'][mask2] = 2;
mask3 = data['length'] > 14;
data['group'][mask3] = 3;
This code is not good, of course. the reason it is not good is because you dont know in run time whether data['group'][mask3], for example, will be a view and thus actually change the dataframe, or it will be a copy and thus the dataframe would remain unchanged. It took me quit sometime to explain it to her, since she argued correctly that she is doing an assignment, not a selection, so the operation should always return a view.
But that was not the strange part. the part the even I couldn't understand is this:
After performing this set of operation, we verified that the assignment took place in two different ways:
By typing data in the console and examining the dataframe summary. It told us we had a few thousand of null values. The number of null values was the same as the size of mask3 so we assumed the last assignment was made on a copy and not on a view.
By typing data.group.value_counts(). That returned 3 values: 1,2 and 3 (surprise) we then typed data.group.value_counts.sum() and it summed up to 12,000!
So by method 2, the group column contained no null values and all the values we wanted it to have. But by method 1 - it didnt!
Can anyone explain this?
see docs here.
You dont' want to set values this way for exactly the reason you pointed; since you don't know if its a view, you don't know that you are actually changing the data. 0.13 will raise/warn that you are attempting to do this, but easiest/best to just access like:
data.loc[mask3,'group'] = 3
which will guarantee you inplace setitem
I have a rinex file and is shown here..an image showing the first part of rinex file
http://imageshack.us/photo/my-images/593/65961409.jpg
The data (AOPR Rinex file) is downloaded from the site after entering a year and a day.
http://www.naic.edu/aisr/GPSTEC/gpstec.html
I want to open this file as a matrix in matlab for further processing..After the end of header at the 42nd line the time information is on 43 rd line. Then data starts. But time information is coming again after some rows say 64 the line, which should be discarded. Header should also be discarded. Also the last column is coming below the first column as a second row which should be transferred to the last column. Totally there are 55700 rows. Kindly help me with this.
I suspect the last column appearing on the line below it is just an artifact of how large the window of your text reader is...
For the rest, I think a trial-and-error loop is in place here:
fid = fopen('test.txt','r');
C = {};
while ~feof(fid)
% read lines with dictated format.
D = textscan(fid, '%d %d %d %d');
% this will fail on headerlines, empty lines, etc.
if isempty(D{1})
% in those cases, advance the file pointer by one line
fgetl(fid);
else
% if that's not the case, save the lines thus read
C = [C;D]; %#ok
end
end
fclose(fid);
% Post-process: concatenate all sub-arrays into one
C = arrayfun(#(ii) cat(1, C{:,ii}), 1:size(C,2), 'UniformOutput', false);
This works, at least with my test.txt:
header
random
garbage
1 2 3 4
4 5 6 7
4 6 7 8
more random garbage
2 5 6 7
5 6 7 8
8 6 3 7
I suspect the last column appearing on the line below it is just an artifact of how large >the window of your text reader is...
For the rest, I think a trial-and-error loop is in place here
Dear Rody I don't have any matlab background and just a beginner. It is actually a Rinex file..with 2780 epochs and 6 observables with 30 satellite values..Decoding it in matlab is tough. That is the problem. You can read a sample code at
http://web.ics.purdue.edu/~tdauterm/EAS591/Lab7/read_rinexo.m
But the problem is that the observables are six and there only 5 in the m-file which also is not in the correct order. I need C1 P2 L1 L2 S1 S2...but the code at the link gives L1 L2 C1 P1 P2. :( Can you just correct that..Then it will be a great help..