Loop over variables

[Abha Indurkar]

input double(month202001 month202002 month202003 month202004 month202005 month202101 month202102 month202103 month202104 month202105 month202201 month202202 month202203 month202204 month202205)
276.16 275.63 276.83 278.39 273.53 290.03 290.3 291.96 293.88 287.92 307.02 308.21 310.12 312.38 309.28
300.11 299.13 300.74 303.39 294.08 315.81 315.35 317.32 320.28 308.41 333.51 334.95 337.43 340.25 334.02
245.46 245.49 246.17 246.34 247.17 256.97 258.18 259.44 260.02 261.65 273.05 273.93 275.11 276.64 277.57
290.95 291 291.44 291.49 291.72 301.15 302.12 303.73 304.23 305.17 321.57 323.49 325.31 328.18 329.4
224.99 225.06 225.93 226.04 226.3 229.98 229.35 229.5 229.44 225.9 233.53 233.65 234.17 234.65 235.01
285.35 284.83 285.51 285.79 285.8 297.45 299.53 302.63 305 306.46 320.51 322.05 323.51 325.93 328.4
232.8 232.88 233.28 233.7 239.36 249.01 250.79 251.13 251.5 251.53 253.44 253.57 253.91 254.59 255.05
248.96 249.14 249.97 250.22 252.04 269.58 272.6 274.68 276.02 294.86 315.7 317.11 317.88 319.82 320.76
190.66 190.69 190.92 190.96 190.96 194.13 195.12 195.89 195.95 195.99 203.16 203.76 204.95 206.59 207.47
262 262.23 263.15 263.41 263.66 291.53 296.15 299.06 299.67 299.99 312.88 314.16 317.85 319.99 321.15
end
[/CODE]


Above is the extract of my data, each variable is consumer price index (cpi) of each year and each month for ex month202001 is cpi of year2020 and month01, I want to create for year 2021 and 2022 the inflation rates for each month using the formula inf_202101=month202001-month202101/month202101, using foreach loop as I have many years in actual data set.

[Øyvind Snilsberg]

maybe,

foreach v of var month202101-month202205 {
local a = real(substr("`v'",6,6))
local b = `a' - 100
gen inf`v'= (month`b' - month`a') / month`a'
}

[Abha Indurkar]

Thank you

[Nick Cox]

Oyvind Snilsberg gave you what you asked for, but working with such a wide layout as you have is at best awkward and at worst a small nightmare. You will be much better off for most Stata purposes with a long layout, as follows:

clear 
input double(month202001 month202002 month202003 month202004 month202005 month202101 month202102 month202103 month202104 month202105 month202201 month202202 month202203 month202204 month202205)
276.16 275.63 276.83 278.39 273.53 290.03 290.3 291.96 293.88 287.92 307.02 308.21 310.12 312.38 309.28
300.11 299.13 300.74 303.39 294.08 315.81 315.35 317.32 320.28 308.41 333.51 334.95 337.43 340.25 334.02
245.46 245.49 246.17 246.34 247.17 256.97 258.18 259.44 260.02 261.65 273.05 273.93 275.11 276.64 277.57
290.95 291 291.44 291.49 291.72 301.15 302.12 303.73 304.23 305.17 321.57 323.49 325.31 328.18 329.4
224.99 225.06 225.93 226.04 226.3 229.98 229.35 229.5 229.44 225.9 233.53 233.65 234.17 234.65 235.01
285.35 284.83 285.51 285.79 285.8 297.45 299.53 302.63 305 306.46 320.51 322.05 323.51 325.93 328.4
232.8 232.88 233.28 233.7 239.36 249.01 250.79 251.13 251.5 251.53 253.44 253.57 253.91 254.59 255.05
248.96 249.14 249.97 250.22 252.04 269.58 272.6 274.68 276.02 294.86 315.7 317.11 317.88 319.82 320.76
190.66 190.69 190.92 190.96 190.96 194.13 195.12 195.89 195.95 195.99 203.16 203.76 204.95 206.59 207.47
262 262.23 263.15 263.41 263.66 291.53 296.15 299.06 299.67 299.99 312.88 314.16 317.85 319.99 321.15
end

gen long id = _n
reshape long month, i(id) j(Mdate)

gen mdate = ym(floor(Mdate/100), mod(Mdate, 100))
format mdate %tm
drop Mdate 
rename month whatever 
l if id == 1 

     +------------------------+
     | id   whatever    mdate |
     |------------------------|
  1. |  1     276.16   2020m1 |
  2. |  1     275.63   2020m2 |
  3. |  1     276.83   2020m3 |
  4. |  1     278.39   2020m4 |
  5. |  1     273.53   2020m5 |
     |------------------------|
  6. |  1     290.03   2021m1 |
  7. |  1      290.3   2021m2 |
  8. |  1     291.96   2021m3 |
  9. |  1     293.88   2021m4 |
 10. |  1     287.92   2021m5 |
     |------------------------|
 11. |  1     307.02   2022m1 |
 12. |  1     308.21   2022m2 |
 13. |  1     310.12   2022m3 |
 14. |  1     312.38   2022m4 |
 15. |  1     309.28   2022m5 |
     +------------------------+

You should already have an identifier, and if so use it rather than create a new one.

[Abha Indurkar]

Thank you for your input, I see what you mean.