Unable to remove part of a string using strrpos ()

[Pragati Godbole]

Hello Stata users,

I am using Stata/IC 15.1 and would like to remove the part of the first string variable that occurs after the second M in the string.

I used the following sequence of commands. However, when I get to the fourth command it only removes the latter part of the string for participants from Oromia but not SNNPR. I would like help with removing the latter part of the string after the second M for the participants of SNNPR as well. (Including data example)

Thank you,


rename A UID

replace UID = subinstr(UID, "_","",.)

replace UID = subinstr(UID, "GEM", "",.)

replace UID = substr(UID,1, strrpos(UID,"M"))

* Example generated by -dataex-. To install: ssc install dataex
clear
input str29 A str4 B str6 C
"GEM_036_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_035_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_034_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_033_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_031_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_032_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_027_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_025_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_026_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_028_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_029_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_030_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_047_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_046_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_045_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_037_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_038_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_039_M25_ORO_15Nov2019-SE"  "Male" "Oromia"
"GEM_040_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_044_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_043_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_042_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
"GEM_041_M25_ORO_17Nov2019-SE"  "Male" "Oromia"
""                              "Male" "Oromia"
"GEM_010_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_023_M15_ORO_22Oct2019-SE"  "Male" "Oromia"
"GEM_024_M25_ORO_23Oct2019-SE"  "Male" "Oromia"
"GEM_022_M25_ORO_22Oct2019-SE"  "Male" "Oromia"
"GEM_021_M25_ORO_22Oct2019-SE"  "Male" "Oromia"
"GEM_020_M25_ORO_22Oct2019-SE"  "Male" "Oromia"
"GEM_019_M25_ORO_22Oct2019-SE"  "Male" "Oromia"
"GEM_018_M25_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_017_M25_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_016_M25_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_009_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_001_M25_ORO_17Oct2019-SE"  "Male" "Oromia"
"GEM_002_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_003_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_004_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_005_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_006_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_007_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_008_M25_ORO_18Oct2019-SE"  "Male" "Oromia"
"GEM_011_M25_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_012_M15_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_013_M15_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_014_M25_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_015_M15_ORO_21Oct2019-SE"  "Male" "Oromia"
"GEM_017_M25_SNNP_17Oct2019-TM" "Male" "SNNPR" 
"GEM_011_M25_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_010_M25_SNNP_21Oct2019-TM" "Male" "SNNPR" 
"GEM_009_M25_SNNP_19Oct2019-TM" "Male" "SNNPR" 
"GEM_008_M25_SNNP_19Oct2019-TM" "Male" "SNNPR" 
"GEM_007_M25_SNNP_18Oct2019-TM" "Male" "SNNPR" 
"GEM_006_M25_SNNP_18Oct2019-TM" "Male" "SNNPR" 
"GEM_005_M25_SNNP_18Oct2019-TM" "Male" "SNNPR" 
"GEM_004_M25_SNNP_17Oct2019-TM" "Male" "SNNPR" 
"GEM_003_M15_SNNP_17Oct2019-TM" "Male" "SNNPR" 
"GEM_002_M25_SNNP_17Oct2019-TM" "Male" "SNNPR" 
"GEM_001_M25_SNNP_17Oct2019-TM" "Male" "SNNPR" 
"GEM_023_M15_SNNP_23Oct2019-TM" "Male" "SNNPR" 
"GEM_022_M25_SNNP_23Oct2019-TM" "Male" "SNNPR" 
"GEM_021_M25_SNNP_23Oct2019-TM" "Male" "SNNPR" 
"GEM_020_M25_SNNP_23Oct2019-TM" "Male" "SNNPR" 
"GEM_019_M25_SNNP_23Oct2019-TM" "Male" "SNNPR" 
"GEM_018_M15_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_016_M25_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_015_M25_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_014_M25_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_013_M25_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_012_M25_SNNP_22Oct2019-TM" "Male" "SNNPR" 
"GEM_024_M25_SNNP_24Oct2019-TM" "Male" "SNNPR" 
"GEM_036_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_034_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_035_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_033_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_032_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_031_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_030_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_028_M25_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_029_M15_SNNP_25Oct2019-TM" "Male" "SNNPR" 
"GEM_027_M25_SNNP_24Oct2019-TM" "Male" "SNNPR" 
"GEM_025_M25_SNNP_24Oct2019-TM" "Male" "SNNPR" 
"GEM_026_M25_SNNP_24Oct2019-TM" "Male" "SNNPR" 
"GEM_041_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_048_M25_SNNP_30Oct2019-TM" "Male" "SNNPR" 
"GEM_047_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_046_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_045_M15_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_044_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_043_M15_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_042_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_040_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_039_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_037_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
"GEM_038_M25_SNNP_28Oct2019-TM" "Male" "SNNPR" 
end

[Wouter Wakker]

It looks like you need strpos instead of strrpos (small but important difference).

[Andrew Musau]

Regular expressions will work well here as well.

rename A UID
replace UID = subinstr(UID, "_","",.)
gen wanted= ustrregexs(0) if ustrregexm(UID,"([0-9]{3})M")

[Pragati Godbole]

Ah! So simple. Thank you for your help!