Notice: On March 31, it was **announced** that Statalist is moving from an email list to a **forum**. The old list will shut down on April 23, and its replacement, **statalist.org** is already up and running.

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

From |
Eric Booth <ebooth@ppri.tamu.edu> |

To |
"<statalist@hsphsun2.harvard.edu>" <statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: saving space while recoding |

Date |
Sat, 24 Jul 2010 21:35:47 +0000 |

<> 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/

**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>

- Prev by Date:
**Re: st: reshape data** - Next by Date:
**Re: st: saving space while recoding** - Previous by thread:
**st: saving space while recoding** - Next by thread:
**Re: st: saving space while recoding** - Index(es):