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

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: saving space while recoding |

Date |
Sun, 25 Jul 2010 21:14:36 -0500 |

Now I have a second list given me where there are some ranges instead of single cutoff points, so for list "newvar2 22 25 newvar3 33.5 26 newvar9 55.5 100 " I need to recode values less than first range point to -1, values between range to zero, and points above the second range point to 1. With the replace command, I can do it: generate var = -1 if newvar2<=22 replace var = 0 if newvar2>=22 & newvar2<=25 replace var = 1 if newvar2>= 25 & newvar2!=. and I tried to paste this into the code I got earlier but it doesnt work. gen var = cond(22<=newvar2<=25, 0, cond(missing(newvar2), ., (cond(newvar2<22, -1, 1)) This gives me all zeros ! How can I edit this code to work with my new list and make this work in a loop to save space ? On Sat, Jul 24, 2010 at 5:58 PM, sarah plank <sarahkplank@gmail.com> wrote: > 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:*Jeph Herrin <stata@spandrel.net>

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

**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>

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

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