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From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: re: return a specific bit from integer variable |

Date |
Mon, 5 Oct 2009 10:57:00 -0400 |

Steinar Fossedal could also try: clear range x 0 255 256 g t=x loc i=1 count if t>0 loc z=r(N) qui while `z'>0 { g bit`i'=mod(t,2^`i')==2^`=`i'-1' replace t=t-bit`i'*2^`=`i'-1' count if t>0 loc z=r(N) loc i=`i'+1 } egen s=concat(bit*) g r=reverse(string(s)) list On Mon, Oct 5, 2009 at 7:47 AM, Nick Cox <n.j.cox@durham.ac.uk> wrote: > See also > > 1. official command -inbase-. > > 2. -egen- function -base()- in -egenmore- from SSC. The help gives an > example that seems parallel to Steinar's problem. > > Note that -split- (as suggested by Martin Weiss) is no help here. > -split- is for strings subdivided by parsing or punctuation characters. > > Nick > n.j.cox@durham.ac.uk > > Kit Baum > > Given an integer between 0-255 and the desired bit to be retrieved > (counting from the left or high-order bit), this routine will give you > the binary form of the integer and the bit as locals: > > mata: mata clear > mata: > void bit(real scalar v, real scalar w) > { > string vector d, b > d=("0000","0001","0010","0011","0100","0101","0110","0111", // > "1000","1001","1010","1011","1100","1101","1110","1111") > for(i=1;i<=cols(d);i++) { > dd = d[i] :+ d > b = b, dd > } > if( v>0 & v <= 255 & w > 0 & w <= 8) { > st_local("v" , b[v+1] ) > st_local("w", substr(b[v+1], w, 1)) > } > } > end > > . mata: bit(128,1) > > . di "`v' `w'" > 10000000 1 > > . mata: bit(128,3) > > . di "`v' `w'" > 10000000 0 > > Steinar Fossedal > ================ > > I have imported an 8-bit integer variable where each bit represents a > flag telling me if some property of the observation is true or false. > > E.g. the number 8 in binary format is 00001000, while 10 would be > 00001010. Bit nr. 4 from the left tells me if a car is delivered or not, > while the second to the right tells me if it's paid or not. So 8 = car > is delivered but not paid, 2 = paid but not delivered, 10 = paid and > delivered, etc. > > I need to split this information into 8 dummyvariables so they can be > used to segment my data. > > Does there exist a fairly smooth way to do this in Stata? * * 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/

**References**:**st: re: return a specific bit from integer variable***From:*Kit Baum <baum@bc.edu>

**st: RE: re: return a specific bit from integer variable***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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