Regression, list of all variables in dataset

Question

Is there Is there a simple (or not so simple) way in R to create a list of all the variables in the dataset?

I'd like to loop across my variables regressing on another variable so I can predict values for each variable under an assumption about my independent variable.

In Stata this looks like

foreach v of var a b c { 
    qui regress `v' i 
    di "`v' {col 2O}" _b[`i'] * 42 
} 

42 is an arbitrary number

For example if I have three variables a, b, and c, and another independent variable i, I'd like to regress a i , regress b i, and regress c i and after each regression take the coef and multiply it by a value of i to predict an outcome.

The problem is that I have an unknown number of variables and I'd like to be able to take the full list and loop across it.

My data structure

structure(list(serial = c(19160206, 19160202, 19160203, 32051017, 
32051017), strata = structure(c(347, 347, 347, 244, 244), label = "Strata", class = c("labelled", 
"numeric")), psu = structure(c(553, 553, 553, 822, 822), label = "Primary sampling unit", class = c("labelled", 
"numeric")), pnum = c(1, 3, 2, 5, 6), DMFlag = structure(c(1, 
4, 3, 3, 3), label = "Final case status flag  (IND)", class = c("labelled", 
"numeric")), HhOut = structure(c(110, 210, 110, 110, 110), label = "Final outcome - household", class = c("labelled", 
"numeric")), IndOut = structure(c(11, 43, 11, 11, 11), label = "Final outcome - individual", class = c("labelled", 
"numeric")), ind_wt = c(0.783649023617231, NA, 0.677951319403552, 
NA, NA), IMonth = structure(c(2, 4, 2, 10, 10), label = "Interview month", class = c("labelled", 
"numeric")), IYear = structure(c(2015, 2015, 2015, 2015, 2015
), label = "Interview Year", class = c("labelled", "numeric")), 
    DMSex = structure(c(2, 1, 1, NA, NA), label = "Gender from household grid", class = c("labelled", 
    "numeric")), DM014 = structure(c(0, 1, 2, NA, NA), label = "Number of children aged 0-14", class = c("labelled", 
    "numeric")), DM016 = structure(c(0, 1, 2, NA, NA), label = "Number of children aged 0-16", class = c("labelled", 
    "numeric")), DM510 = structure(c(0, 0, 1, NA, NA), label = "Number of children aged 5-10", class = c("labelled", 
    "numeric")), DM1115 = structure(c(0, 1, 1, NA, NA), label = "Number of children aged 11-15", class = c("labelled", 
    "numeric")), DM1619 = structure(c(0, 0, 0, NA, NA), label = "Number of children aged 16-19", class = c("labelled", 
    "numeric")), WorkSta = structure(c(4, -1, -1, NA, NA), label = "Economic activity status", class = c("labelled", 
    "numeric")), act1_1 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 04:00-04:10", class = c("labelled", 
    "numeric")), act1_2 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 04:10-04:20", class = c("labelled", 
    "numeric")), act1_3 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 04:20-04:30", class = c("labelled", 
    "numeric")), act1_4 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 04:30-04:40", class = c("labelled", 
    "numeric")), act1_5 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 04:40-04:50", class = c("labelled", 
    "numeric")), act1_6 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 04:50-05:00", class = c("labelled", 
    "numeric")), act1_7 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 05:00-05:10", class = c("labelled", 
    "numeric")), act1_8 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 05:10-05:20", class = c("labelled", 
    "numeric")), act1_9 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 05:20-05:30", class = c("labelled", 
    "numeric")), act1_10 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 05:30-05:40", class = c("labelled", 
    "numeric")), act1_11 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 05:40-05:50", class = c("labelled", 
    "numeric")), act1_12 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 05:50-06:00", class = c("labelled", 
    "numeric")), act1_13 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 06:00-06:10", class = c("labelled", 
    "numeric")), act1_14 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 06:10-06:20", class = c("labelled", 
    "numeric")), act1_15 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 06:20-06:30", class = c("labelled", 
    "numeric")), act1_16 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 06:30-06:40", class = c("labelled", 
    "numeric")), act1_17 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 06:40-06:50", class = c("labelled", 
    "numeric")), act1_18 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 06:50-07:00", class = c("labelled", 
    "numeric")), act1_19 = structure(c(110, 110, 110, 111, 110
    ), label = "Primary activity: 07:00-07:10", class = c("labelled", 
    "numeric")), act1_20 = structure(c(110, 110, 110, 111, 110
    ), label = "Primary activity: 07:10-07:20", class = c("labelled", 
    "numeric")), act1_21 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 07:20-07:30", class = c("labelled", 
    "numeric")), act1_22 = structure(c(110, 110, 110, 111, 110
    ), label = "Primary activity: 07:30-07:40", class = c("labelled", 
    "numeric")), act1_23 = structure(c(110, 110, 110, 111, 110
    ), label = "Primary activity: 07:40-07:50", class = c("labelled", 
    "numeric")), act1_24 = structure(c(110, 110, 110, 310, 110
    ), label = "Primary activity: 07:50-08:00", class = c("labelled", 
    "numeric")), act1_25 = structure(c(110, 110, 110, 3110, 111
    ), label = "Primary activity: 08:00-08:10", class = c("labelled", 
    "numeric")), act1_26 = structure(c(110, 110, 110, 310, 210
    ), label = "Primary activity: 08:10-08:20", class = c("labelled", 
    "numeric")), act1_27 = structure(c(110, 110, 110, 310, 3130
    ), label = "Primary activity: 08:20-08:30", class = c("labelled", 
    "numeric")), act1_28 = structure(c(310, 110, 110, 310, 310
    ), label = "Primary activity: 08:30-08:40", class = c("labelled", 
    "numeric")), act1_29 = structure(c(310, 110, 110, 9610, 9610
    ), label = "Primary activity: 08:40-08:50", class = c("labelled", 
    "numeric")), act1_30 = structure(c(7330, 110, 110, 6190, 
    6190), label = "Primary activity: 08:50-09:00", class = c("labelled", 
    "numeric")), act1_31 = structure(c(8210, 110, 110, 6190, 
    6190), label = "Primary activity: 09:00-09:10", class = c("labelled", 
    "numeric")), act1_32 = structure(c(8210, 110, 110, 6190, 
    6190), label = "Primary activity: 09:10-09:20", class = c("labelled", 
    "numeric")), act1_33 = structure(c(8210, 310, 110, 6190, 
    6190), label = "Primary activity: 09:20-09:30", class = c("labelled", 
    "numeric")), act1_34 = structure(c(8210, 310, 310, 6190, 
    6190), label = "Primary activity: 09:30-09:40", class = c("labelled", 
    "numeric")), act1_35 = structure(c(8210, 5110, 210, 6190, 
    6190), label = "Primary activity: 09:40-09:50", class = c("labelled", 
    "numeric")), act1_36 = structure(c(8210, 5110, 310, 6190, 
    6190), label = "Primary activity: 09:50-10:00", class = c("labelled", 
    "numeric")), act1_37 = structure(c(8210, 5110, 7330, 6190, 
    6190), label = "Primary activity: 10:00-10:10", class = c("labelled", 
    "numeric")), act1_38 = structure(c(8210, 9510, 7330, 6190, 
    6190), label = "Primary activity: 10:10-10:20", class = c("labelled", 
    "numeric")), act1_39 = structure(c(8210, 9510, 7330, 6190, 
    6190), label = "Primary activity: 10:20-10:30", class = c("labelled", 
    "numeric")), act1_40 = structure(c(8210, 3611, 7330, 6190, 
    6190), label = "Primary activity: 10:30-10:40", class = c("labelled", 
    "numeric")), act1_41 = structure(c(8210, 210, 7330, 9610, 
    6190), label = "Primary activity: 10:40-10:50", class = c("labelled", 
    "numeric")), act1_42 = structure(c(8210, 210, 7330, 6190, 
    6190), label = "Primary activity: 10:50-11:00", class = c("labelled", 
    "numeric")), act1_43 = structure(c(8210, 9510, 7330, 6190, 
    9610), label = "Primary activity: 11:00-11:10", class = c("labelled", 
    "numeric")), act1_44 = structure(c(8210, 9510, 7330, 6190, 
    6190), label = "Primary activity: 11:10-11:20", class = c("labelled", 
    "numeric")), act1_45 = structure(c(8210, 3290, 8210, 6190, 
    6190), label = "Primary activity: 11:20-11:30", class = c("labelled", 
    "numeric")), act1_46 = structure(c(3240, 3210, 8210, 6190, 
    6190), label = "Primary activity: 11:30-11:40", class = c("labelled", 
    "numeric")), act1_47 = structure(c(3240, 3210, 8210, 6190, 
    6190), label = "Primary activity: 11:40-11:50", class = c("labelled", 
    "numeric")), act1_48 = structure(c(3210, 3210, 8210, 6190, 
    6150), label = "Primary activity: 11:50-12:00", class = c("labelled", 
    "numeric")), act1_49 = structure(c(3210, 3210, 8210, 6190, 
    6150), label = "Primary activity: 12:00-12:10", class = c("labelled", 
    "numeric")), act1_50 = structure(c(8210, 3210, 9370, 5310, 
    6150), label = "Primary activity: 12:10-12:20", class = c("labelled", 
    "numeric")), act1_51 = structure(c(8210, 3210, 9370, 5310, 
    6150), label = "Primary activity: 12:20-12:30", class = c("labelled", 
    "numeric")), act1_52 = structure(c(8210, 5140, 9370, 5310, 
    9610), label = "Primary activity: 12:30-12:40", class = c("labelled", 
    "numeric")), act1_53 = structure(c(8210, 3210, 9370, 5310, 
    3290), label = "Primary activity: 12:40-12:50", class = c("labelled", 
    "numeric")), act1_54 = structure(c(8210, 3210, 9370, 5310, 
    5140), label = "Primary activity: 12:50-13:00", class = c("labelled", 
    "numeric")), act1_55 = structure(c(8210, 3210, 5190, 5310, 
    310), label = "Primary activity: 13:00-13:10", class = c("labelled", 
    "numeric")), act1_56 = structure(c(8210, 3210, 3630, 5310, 
    310), label = "Primary activity: 13:10-13:20", class = c("labelled", 
    "numeric")), act1_57 = structure(c(8210, 5120, 3630, 5310, 
    6311), label = "Primary activity: 13:20-13:30", class = c("labelled", 
    "numeric")), act1_58 = structure(c(8210, 9500, 3630, 6150, 
    5120), label = "Primary activity: 13:30-13:40", class = c("labelled", 
    "numeric")), act1_59 = structure(c(8210, 3290, 5190, 6150, 
    9510), label = "Primary activity: 13:40-13:50", class = c("labelled", 
    "numeric")), act1_60 = structure(c(8210, 210, 6110, 6150, 
    5130), label = "Primary activity: 13:50-14:00", class = c("labelled", 
    "numeric")), act1_61 = structure(c(8210, 210, 6110, 6150, 
    6190), label = "Primary activity: 14:00-14:10", class = c("labelled", 
    "numeric")), act1_62 = structure(c(8210, 5120, 6110, 9610, 
    6190), label = "Primary activity: 14:10-14:20", class = c("labelled", 
    "numeric")), act1_63 = structure(c(8210, 5120, 6110, 3110, 
    6190), label = "Primary activity: 14:20-14:30", class = c("labelled", 
    "numeric")), act1_64 = structure(c(9500, 5120, 6110, 8210, 
    5310), label = "Primary activity: 14:30-14:40", class = c("labelled", 
    "numeric")), act1_65 = structure(c(9500, 5120, 6110, 310, 
    5310), label = "Primary activity: 14:40-14:50", class = c("labelled", 
    "numeric")), act1_66 = structure(c(9990, 9360, 6110, 310, 
    5310), label = "Primary activity: 14:50-15:00", class = c("labelled", 
    "numeric")), act1_67 = structure(c(8210, 9360, 6110, 210, 
    6190), label = "Primary activity: 15:00-15:10", class = c("labelled", 
    "numeric")), act1_68 = structure(c(8210, 9360, 6110, 9610, 
    6190), label = "Primary activity: 15:10-15:20", class = c("labelled", 
    "numeric")), act1_69 = structure(c(8210, 3610, 6110, 6171, 
    6190), label = "Primary activity: 15:20-15:30", class = c("labelled", 
    "numeric")), act1_70 = structure(c(8210, 3610, 6110, 6171, 
    210), label = "Primary activity: 15:30-15:40", class = c("labelled", 
    "numeric")), act1_71 = structure(c(8210, 3610, 6110, 6171, 
    210), label = "Primary activity: 15:40-15:50", class = c("labelled", 
    "numeric")), act1_72 = structure(c(8210, 3610, 6110, 6171, 
    6190), label = "Primary activity: 15:50-16:00", class = c("labelled", 
    "numeric")), act1_73 = structure(c(7330, 3610, 6110, 6171, 
    6190), label = "Primary activity: 16:00-16:10", class = c("labelled", 
    "numeric")), act1_74 = structure(c(7330, 3610, 6110, 6171, 
    6190), label = "Primary activity: 16:10-16:20", class = c("labelled", 
    "numeric")), act1_75 = structure(c(7330, 3610, 6110, 6171, 
    5310), label = "Primary activity: 16:20-16:30", class = c("labelled", 
    "numeric")), act1_76 = structure(c(7330, 3610, 6110, 310, 
    9510), label = "Primary activity: 16:30-16:40", class = c("labelled", 
    "numeric")), act1_77 = structure(c(7330, 3610, 6110, 310, 
    9510), label = "Primary activity: 16:40-16:50", class = c("labelled", 
    "numeric")), act1_78 = structure(c(8210, 3610, 9500, 310, 
    9510), label = "Primary activity: 16:50-17:00", class = c("labelled", 
    "numeric")), act1_79 = structure(c(8210, 3610, 9500, 310, 
    7241), label = "Primary activity: 17:00-17:10", class = c("labelled", 
    "numeric")), act1_80 = structure(c(8210, 3610, 3611, 3611, 
    7241), label = "Primary activity: 17:10-17:20", class = c("labelled", 
    "numeric")), act1_81 = structure(c(210, 9360, 5310, 9500, 
    8210), label = "Primary activity: 17:20-17:30", class = c("labelled", 
    "numeric")), act1_82 = structure(c(210, 9360, 210, 4230, 
    8210), label = "Primary activity: 17:30-17:40", class = c("labelled", 
    "numeric")), act1_83 = structure(c(210, 9360, 210, 4230, 
    8210), label = "Primary activity: 17:40-17:50", class = c("labelled", 
    "numeric")), act1_84 = structure(c(7330, 9360, 9520, 4230, 
    8210), label = "Primary activity: 17:50-18:00", class = c("labelled", 
    "numeric")), act1_85 = structure(c(7330, 9360, 3290, 4230, 
    8210), label = "Primary activity: 18:00-18:10", class = c("labelled", 
    "numeric")), act1_86 = structure(c(7330, 4220, 5310, 4230, 
    8210), label = "Primary activity: 18:10-18:20", class = c("labelled", 
    "numeric")), act1_87 = structure(c(7330, 4220, 5310, 8219, 
    3210), label = "Primary activity: 18:20-18:30", class = c("labelled", 
    "numeric")), act1_88 = structure(c(8210, 5310, 5310, 8219, 
    3210), label = "Primary activity: 18:30-18:40", class = c("labelled", 
    "numeric")), act1_89 = structure(c(8210, 5310, 5310, 8219, 
    3210), label = "Primary activity: 18:40-18:50", class = c("labelled", 
    "numeric")), act1_90 = structure(c(8210, 5100, 5310, 8219, 
    3210), label = "Primary activity: 18:50-19:00", class = c("labelled", 
    "numeric")), act1_91 = structure(c(8210, 5120, 7330, 8219, 
    5140), label = "Primary activity: 19:00-19:10", class = c("labelled", 
    "numeric")), act1_92 = structure(c(8210, 5120, 7330, 8219, 
    5140), label = "Primary activity: 19:10-19:20", class = c("labelled", 
    "numeric")), act1_93 = structure(c(8210, 5120, 7330, 8219, 
    5140), label = "Primary activity: 19:20-19:30", class = c("labelled", 
    "numeric")), act1_94 = structure(c(8210, 9360, 7330, 8219, 
    210), label = "Primary activity: 19:30-19:40", class = c("labelled", 
    "numeric")), act1_95 = structure(c(8210, 3610, 7330, 8219, 
    210), label = "Primary activity: 19:40-19:50", class = c("labelled", 
    "numeric")), act1_96 = structure(c(8210, 9360, 7330, 8219, 
    210), label = "Primary activity: 19:50-20:00", class = c("labelled", 
    "numeric")), act1_97 = structure(c(8210, 3290, 7330, 8219, 
    210), label = "Primary activity: 20:00-20:10", class = c("labelled", 
    "numeric")), act1_98 = structure(c(8210, 5310, 7330, 8219, 
    8210), label = "Primary activity: 20:10-20:20", class = c("labelled", 
    "numeric")), act1_99 = structure(c(310, 210, 7330, 8219, 
    8210), label = "Primary activity: 20:20-20:30", class = c("labelled", 
    "numeric")), act1_100 = structure(c(310, 210, 7330, 9500, 
    8210), label = "Primary activity: 20:30-20:40", class = c("labelled", 
    "numeric")), act1_101 = structure(c(111, 3110, 7330, 8219, 
    8210), label = "Primary activity: 20:40-20:50", class = c("labelled", 
    "numeric")), act1_102 = structure(c(111, 3110, 7330, 8219, 
    8210), label = "Primary activity: 20:50-21:00", class = c("labelled", 
    "numeric")), act1_103 = structure(c(111, 210, 7330, 8219, 
    8210), label = "Primary activity: 21:00-21:10", class = c("labelled", 
    "numeric")), act1_104 = structure(c(110, 210, 7330, 8219, 
    8210), label = "Primary activity: 21:10-21:20", class = c("labelled", 
    "numeric")), act1_105 = structure(c(110, 8210, 7330, 8219, 
    8210), label = "Primary activity: 21:20-21:30", class = c("labelled", 
    "numeric")), act1_106 = structure(c(110, 8210, 7330, 8219, 
    8210), label = "Primary activity: 21:30-21:40", class = c("labelled", 
    "numeric")), act1_107 = structure(c(110, 8210, 7330, 8219, 
    8210), label = "Primary activity: 21:40-21:50", class = c("labelled", 
    "numeric")), act1_108 = structure(c(110, 8210, 7330, 8219, 
    8210), label = "Primary activity: 21:50-22:00", class = c("labelled", 
    "numeric")), act1_109 = structure(c(110, 8210, 7330, 310, 
    310), label = "Primary activity: 22:00-22:10", class = c("labelled", 
    "numeric")), act1_110 = structure(c(110, 8210, 7330, 310, 
    310), label = "Primary activity: 22:10-22:20", class = c("labelled", 
    "numeric")), act1_111 = structure(c(110, 8210, 7330, 111, 
    310), label = "Primary activity: 22:20-22:30", class = c("labelled", 
    "numeric")), act1_112 = structure(c(110, 8210, 7330, 111, 
    310), label = "Primary activity: 22:30-22:40", class = c("labelled", 
    "numeric")), act1_113 = structure(c(110, 8210, 7330, 110, 
    310), label = "Primary activity: 22:40-22:50", class = c("labelled", 
    "numeric")), act1_114 = structure(c(110, 8210, 7330, 110, 
    110), label = "Primary activity: 22:50-23:00", class = c("labelled", 
    "numeric")), act1_115 = structure(c(110, 8210, 8210, 110, 
    110), label = "Primary activity: 23:00-23:10", class = c("labelled", 
    "numeric")), act1_116 = structure(c(110, 8210, 8210, 110, 
    110), label = "Primary activity: 23:10-23:20", class = c("labelled", 
    "numeric")), act1_117 = structure(c(110, 8210, 8210, 110, 
    110), label = "Primary activity: 23:20-23:30", class = c("labelled", 
    "numeric")), act1_118 = structure(c(110, 8210, 8210, 110, 
    110), label = "Primary activity: 23:30-23:40", class = c("labelled", 
    "numeric")), act1_119 = structure(c(110, 8210, 110, 110, 
    110), label = "Primary activity: 23:40-23:50", class = c("labelled", 
    "numeric")), act1_120 = structure(c(110, 310, 110, 110, 110
    ), label = "Primary activity: 23:50-00:00", class = c("labelled", 
    "numeric")), act1_121 = structure(c(110, 310, 110, 110, 110
    ), label = "Primary activity: 00:00-00:10", class = c("labelled", 
    "numeric")), act1_122 = structure(c(110, 8120, 110, 110, 
    110), label = "Primary activity: 00:10-00:20", class = c("labelled", 
    "numeric")), act1_123 = structure(c(110, 8120, 110, 110, 
    110), label = "Primary activity: 00:20-00:30", class = c("labelled", 
    "numeric")), act1_124 = structure(c(110, 8120, 110, 110, 
    110), label = "Primary activity: 00:30-00:40", class = c("labelled", 
    "numeric")), act1_125 = structure(c(110, 8120, 110, 110, 
    110), label = "Primary activity: 00:40-00:50", class = c("labelled", 
    "numeric")), act1_126 = structure(c(110, 8120, 110, 110, 
    110), label = "Primary activity: 00:50-01:00", class = c("labelled", 
    "numeric")), act1_127 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 01:00-01:10", class = c("labelled", 
    "numeric")), act1_128 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 01:10-01:20", class = c("labelled", 
    "numeric")), act1_129 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 01:20-01:30", class = c("labelled", 
    "numeric")), act1_130 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 01:30-01:40", class = c("labelled", 
    "numeric")), act1_131 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 01:40-01:50", class = c("labelled", 
    "numeric")), act1_132 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 01:50-02:00", class = c("labelled", 
    "numeric")), act1_133 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 02:00-02:10", class = c("labelled", 
    "numeric")), act1_134 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 02:10-02:20", class = c("labelled", 
    "numeric")), act1_135 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 02:20-02:30", class = c("labelled", 
    "numeric")), act1_136 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 02:30-02:40", class = c("labelled", 
    "numeric")), act1_137 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 02:40-02:50", class = c("labelled", 
    "numeric")), act1_138 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 02:50-03:00", class = c("labelled", 
    "numeric")), act1_139 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 03:00-03:10", class = c("labelled", 
    "numeric")), act1_140 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 03:10-03:20", class = c("labelled", 
    "numeric")), act1_141 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 03:20-03:30", class = c("labelled", 
    "numeric")), act1_142 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 03:30-03:40", class = c("labelled", 
    "numeric")), act1_143 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 03:40-03:50", class = c("labelled", 
    "numeric")), act1_144 = structure(c(110, 110, 110, 110, 110
    ), label = "Primary activity: 03:50-04:00", class = c("labelled", 
    "numeric"))), .Names = c("serial", "strata", "psu", "pnum", 
"DMFlag", "HhOut", "IndOut", "ind_wt", "IMonth", "IYear", "DMSex", 
"DM014", "DM016", "DM510", "DM1115", "DM1619", "WorkSta", "act1_1", 
"act1_2", "act1_3", "act1_4", "act1_5", "act1_6", "act1_7", "act1_8", 
"act1_9", "act1_10", "act1_11", "act1_12", "act1_13", "act1_14", 
"act1_15", "act1_16", "act1_17", "act1_18", "act1_19", "act1_20", 
"act1_21", "act1_22", "act1_23", "act1_24", "act1_25", "act1_26", 
"act1_27", "act1_28", "act1_29", "act1_30", "act1_31", "act1_32", 
"act1_33", "act1_34", "act1_35", "act1_36", "act1_37", "act1_38", 
"act1_39", "act1_40", "act1_41", "act1_42", "act1_43", "act1_44", 
"act1_45", "act1_46", "act1_47", "act1_48", "act1_49", "act1_50", 
"act1_51", "act1_52", "act1_53", "act1_54", "act1_55", "act1_56", 
"act1_57", "act1_58", "act1_59", "act1_60", "act1_61", "act1_62", 
"act1_63", "act1_64", "act1_65", "act1_66", "act1_67", "act1_68", 
"act1_69", "act1_70", "act1_71", "act1_72", "act1_73", "act1_74", 
"act1_75", "act1_76", "act1_77", "act1_78", "act1_79", "act1_80", 
"act1_81", "act1_82", "act1_83", "act1_84", "act1_85", "act1_86", 
"act1_87", "act1_88", "act1_89", "act1_90", "act1_91", "act1_92", 
"act1_93", "act1_94", "act1_95", "act1_96", "act1_97", "act1_98", 
"act1_99", "act1_100", "act1_101", "act1_102", "act1_103", "act1_104", 
"act1_105", "act1_106", "act1_107", "act1_108", "act1_109", "act1_110", 
"act1_111", "act1_112", "act1_113", "act1_114", "act1_115", "act1_116", 
"act1_117", "act1_118", "act1_119", "act1_120", "act1_121", "act1_122", 
"act1_123", "act1_124", "act1_125", "act1_126", "act1_127", "act1_128", 
"act1_129", "act1_130", "act1_131", "act1_132", "act1_133", "act1_134", 
"act1_135", "act1_136", "act1_137", "act1_138", "act1_139", "act1_140", 
"act1_141", "act1_142", "act1_143", "act1_144"), row.names = c(NA, 
5L), class = "data.frame")

duckmayr duckmayr · Accepted Answer · 2019-02-08T16:18:55

Below is an inelegant but effective method. First, since your data seem a little messier than is necessary to get the point of this method across: I've created a toy example dataset:

# Set the seed for reproducibility
set.seed(123)
# Create our variables
i <- rnorm(30) # explanatory variable of interest
A <- 5 * i + rnorm(30) # DV 1 -- true coefficient of 5
B <- -2 * i + rnorm(30) # DV 2 -- true coefficient of -2
C <- rnorm(30) # DV 3 -- true coefficient of 0 (independent of i)
# Make a dataframe out of them
dataset <- data.frame(A, B, C, i)

Do run these regressions, we'll get the names of each column we want to use as a DV, then use a combination of as.formula() and paste0() to create the appropriate formulas inside lm():

# And do the regressions
DVnames <- setdiff(colnames(dataset), "i")
models <- lapply(DVnames, function(j) {
    # For every column name j of your dataframe *except* i,
    # Run a linear regression with j as the DV and i as the IV
    lm(as.formula(paste0(j, " ~ i")), data = dataset)
})

Now we can take a look at the results and do the predictions you're looking for:

# Check the results
for ( model in models ) {
    print(summary(model))
}
#> 
#> Call:
#> lm(formula = as.formula(paste0(j, " ~ i")), data = dataset)
#> 
#> Residuals:
#>     Min      1Q  Median      3Q     Max 
#> -1.6085 -0.5056 -0.2152  0.6932  2.0118 
#> 
#> Coefficients:
#>             Estimate Std. Error t value Pr(>|t|)    
#> (Intercept)   0.1720     0.1534   1.121    0.272    
#> i             4.8660     0.1589  30.629   <2e-16 ***
#> ---
#> Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
#> 
#> Residual standard error: 0.8393 on 28 degrees of freedom
#> Multiple R-squared:  0.971,  Adjusted R-squared:   0.97 
#> F-statistic: 938.1 on 1 and 28 DF,  p-value: < 2.2e-16
#>

#> Call:
#> lm(formula = as.formula(paste0(j, " ~ i")), data = dataset)
#> 
#> Residuals:
#>      Min       1Q   Median       3Q      Max 
#> -2.39301 -0.56909  0.03468  0.51764  2.08387 
#> 
#> Coefficients:
#>             Estimate Std. Error t value Pr(>|t|)    
#> (Intercept)   0.0313     0.1596   0.196    0.846    
#> i            -1.8540     0.1653 -11.218 7.18e-12 ***
#> ---
#> Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
#> 
#> Residual standard error: 0.8731 on 28 degrees of freedom
#> Multiple R-squared:  0.818,  Adjusted R-squared:  0.8115 
#> F-statistic: 125.8 on 1 and 28 DF,  p-value: 7.177e-12
#>

#> Call:
#> lm(formula = as.formula(paste0(j, " ~ i")), data = dataset)
#> 
#> Residuals:
#>     Min      1Q  Median      3Q     Max 
#> -1.4989 -0.6435 -0.1436  0.5917  2.2613 
#> 
#> Coefficients:
#>             Estimate Std. Error t value Pr(>|t|)
#> (Intercept) -0.09205    0.16855  -0.546    0.589
#> i            0.03914    0.17454   0.224    0.824
#> 
#> Residual standard error: 0.9221 on 28 degrees of freedom
#> Multiple R-squared:  0.001793,   Adjusted R-squared:  -0.03386 
#> F-statistic: 0.05029 on 1 and 28 DF,  p-value: 0.8242

# And do your predictions
lapply(models, function(model) {
    predict(model, newdata = data.frame(i = 42))
})
#> [[1]]
#>        1 
#> 204.5426 
#> 
#> [[2]]
#>        1 
#> -77.8355 
#> 
#> [[3]]
#>        1 
#> 1.551869

^{Created on 2019-02-08 by the reprex package (v0.2.1)}

You should note that this approach is fairly similar to this answer to a related question (how to mimic a Stata macro for explanatory variables). The main difference, and why I felt like your question deserved a separate answer, is that since you have multiple DVs, you need to run lm() multiple times, which changes the approach somewhat. Whereas in that question, using as.formula() and paste() in one lm() call was sufficient (i.e., lm(as.formula(paste("income~", paste(regressors, collapse="+"))), data = Duncan)), here we need to use that approach in a loop or *apply() call (i.e., lapply(DVnames, function(j) { lm(as.formula(paste0(j, " ~ i")), data = dataset) })). We also then need to use an *apply() function to do the predictions you need.

Regression, list of all variables in dataset

1 Answers