Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
Maarten Buis <maartenlbuis@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Create a row matrix with weighted frequencies from various dummy variables |

Date |
Fri, 1 Jul 2011 13:01:10 +0200 |

2011/7/1 Nikolaos Kanellopoulos: > I have two sets of dummy variables (say d1,...,d20 and z1,...,z5) and I want to > create a 1x100 matrix where each element will be the weighted frequency for each > combination between each d-variable and each z-variable when both equal 1 I think the easiest way to achieve this goal is -collapse- your data. In the example below I used the trick that a frequency is the sum of a "variable" containing only 1s to get the weighted frequency. You can use -mkmat- to turn this into a matrix. You can precede this with -preserve- and end it with -restore- to keep access to the original data. *------------ begin example ---------------- clear set seed 10235 drop _all set obs 1000 /*Generate data*/ gen d = ceil(20*uniform()) gen z = ceil(5*uniform()) generate wt = uniform() gen byte one = 1 collapse (sum) one [pw=wt], by(d z) *--------------- end example ---------------- (For more on examples I sent to the Statalist see: http://www.maartenbuis.nl/example_faq ) Hope this helps, Maarten PS. I presume that the d and z dummies in your example were supposed to represent the different categories in two categorical variables (d and z). In that case the dummies should be mutually exclusive and exhaustive and the way you simulated your data did not achieve that goal. I used tricks from (Buis 2007) to generate these categorical variables. Maarten Buis (2007) "Stata tip 48: Discrete uses for uniform()" The Stata Journal, 7(3): 434-435. <http://www.stata-journal.com/article.html?article=pr0032> -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: Create a row matrix with weighted frequencies from various dummy variables***From:*Nikolaos Kanellopoulos <nkkanel@yahoo.gr>

**References**:**st: Create a row matrix with weighted frequencies from various dummy variables***From:*Nikolaos Kanellopoulos <nkkanel@yahoo.gr>

- Prev by Date:
**st: Program and abstracts for 2011 UK Stata User Meeting** - Next by Date:
**st: RE: Create a row matrix with weighted frequencies from various dummy variables** - Previous by thread:
**st: Create a row matrix with weighted frequencies from various dummy variables** - Next by thread:
**Re: st: Create a row matrix with weighted frequencies from various dummy variables** - Index(es):