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From |
sarah plank <sarahkplank@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: saving space while recoding |

Date |
Sat, 24 Jul 2010 17:58:47 -0500 |

Oh my gosh, how great! I copied and pasted my list into the first example and it is working, I am running it now but I hope it doesnot break because I dont understand it enough to make changes. Thanks. On Sat, Jul 24, 2010 at 4:35 PM, Eric Booth <ebooth@ppri.tamu.edu> wrote: > <> > > > There are a couple of possibilities here. First, you can get rid of the 3 -replace- statements with one -recode- statement that does the same thing, e.g., > > ******! > recode polyclornew (min/44 = -1) (45=0) (46/max = 1) (.=.) > ******! > > but this doesn't make managing your long list of recode conditions much easier. Also, a warning: note that the -replace- codes in your example will not recode any values between 44 and 45 (such as 44.5) nor values between 45 & 46. Given that a lot of the values in the list your provided aren't integers, this might be a concern. > > In terms of making your code shorter you might consider using the -cond()- function. For example, > **********************! > sysuse auto, clear > keep price > qui g i = cond(price==4099, 0, cond(missing(price), ., (cond(price<4099, -1, 1)))) > sort price > **********************! > will recode price around the 4,099 threshold. > A brief explanation of what this code is doing is probably helpful here: if price is == 4099 it will recode i to 0. If not, it will evaluate the last "cond(missing(price), ., (cond(price<4099, -1, 1)) " part. Within this last part it will recode i to -1 if price is less than 4099 and i to 1 if price is greater than or equal to 4099 (but it has already recoded to 0 if price is equal to 4099, so it will just recode to 1 if price is greater than 4099 in this case) . See -help cond- for more. > > To make this work with a long list of conditions like the ones you have provided, you could break the list up into macros &/or use -tokenize- to loop over the pairs of items in your list. Here are two examples using the -auto.dta- again: > > > **********************! > //EXAMPLE 1// > /* > This example uses the list if it is formatted as you presented it in your posting--it will make the changes to items 1 (mpg) and 2(23) in the list and then move on the items 3 and 4 in the list and so on to the end > */ > > sysuse auto, clear > local list mpg 23 rep78 3 turn 17 weight 2930 length 196 > ** > token `"`list'"' > di `"`list'"' > while "`1'" != "" { > di "recode `1' for value `2'" > g i`1' = cond(`1'==`2', 0, cond(missing(`1'), ., (cond(`1'<`2', -1, 1)))) > mac shift 2 //this part increases the macro `1' by 2 to `3' > } > sort mpg > order *mpg > **********************! > > Alternatively, if your list were organized down a column in a spreadsheet or something, you could add -local- and a macname to each pair of items to be used for the recodes and loop over each condition. > > **********************! > //EXAMPLE 2// > sysuse auto, clear > > **items in your list: > local one mpg 23 > local two rep78 3 > local three turn 17 > local four weight 2930 > local five length 196 > > foreach x in one two three four five { > token ``x'' > di "``x''" > di "recode `1' for value `2'" > g i`1' = cond(`1'==`2', 0, cond(missing(`1'), ., (cond(`1'<`2', -1, 1)))) > } > sort mpg > order *mpg > **********************! > > ~ Eric > __ > Eric A. Booth > Public Policy Research Institute > Texas A&M University > ebooth@ppri.tamu.edu > Office: +979.845.6754 > > > > > > On Jul 24, 2010, at 4:22 PM, sarah plank wrote: > >> I need to create a recode but save some space in my code. I have >> lots of recodes where I am given the variable to recode and the cutoff >> point over which to recode the variables. So, given my list of >> "polyclor 23.4 polyclor2 33.3 pavol 45 genpt 1.11 gnpt 1 on >> 0 offon 0 offon2 1 got5 66 {+ 670 more items}" I need to recode >> them all by their cutoff in the list, so >> >> clonevar polyclor2 = polyclornew >> replace polyclornew = -1 if polychlornew<44 >> replace polyclornew = 0 if polyclornew==45 >> replace polyclornew = 1 if polyclornew>46 & polyclornew!=. >> tab polyclornew >> >> but this is so exhausting for so many values and so long in the >> do-code. How can I make this in less space ? >> >> * >> * 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/ > > > > > > * > * 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/ > * * 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: saving space while recoding***From:*sarah plank <sarahkplank@gmail.com>

**References**:**st: saving space while recoding***From:*sarah plank <sarahkplank@gmail.com>

**Re: st: saving space while recoding***From:*Eric Booth <ebooth@ppri.tamu.edu>

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