Thanks very much A.K. I have to admit that my problem was not clearly stated, with the structure of my data provided. Now all is well. Â Cheers Lexi
________________________________ Cc: R help <r-help@r-project.org> Sent: Monday, July 2, 2012 4:40 PM Subject: Re: [R] Adjusting length of series Hello, The class of your data is not dataframe. Suppose I call your data as ydat1 str(ydat1)  mts [1:24, 1:7] 68.1 -34.8 90.4 54.6 -172.3 ...  - attr(*, "dimnames")=List of 2  ..$ : NULL  ..$ : chr [1:7] "DCred1" "DCred2" "DCred3" "DBoBC2" ...  - attr(*, "tsp")= num [1:3] 2001 2003 12  - attr(*, "class")= chr [1:2] "mts" "ts" ydat2<-data.frame(ydat1) str(ydat2) 'data.frame':   24 obs. of 7 variables:  $ DCred1: num 68.1 -34.8 90.4 54.6 -172.3 ...  $ DCred2: num NA -102.9 125.2 -35.8 -226.9 ...  $ DCred3: num NA NA 228 -161 -191 ...  $ DBoBC2: num NA -164.5 17.1 96 680.2 ...  $ DBoBC3: num NA NA 181.5 78.9 584.3 ...  $ CredL1: num 4937 5005 4970 5061 5115 ...  $ BoBCL1: num 4188 4296 4240 4201 4258 ... #Since you wanted only to do lm for these columns, I guess it doesn't really matter whether you have month and year in the dataset.  #With NAs  regCred<-lm(DCred1~DCred2+DCred3+DBoBC2+DBoBC3+CredL1+BoBCL1,data=ydat2) > summary(regCred) Call: lm(formula = DCred1 ~ DCred2 + DCred3 + DBoBC2 + DBoBC3 + CredL1 +    BoBCL1, data = ydat2) Residuals:        Min         1Q     Median         3Q        Max -124.988463 -33.133975   7.971083  23.607953  76.813601 Coefficients:                 Estimate   Std. Error t value  Pr(>|t|)   (Intercept) -538.61375718 205.91179535 -2.61575  0.020344 * DCred2        0.96401908   0.15623660 6.17025 2.4337e-05 *** DCred3       -0.25720355   0.08983607 -2.86303  0.012524 * DBoBC2       -0.11222347   0.07828182 -1.43358  0.173646   DBoBC3        0.04564621   0.03825169 1.19331  0.252578   CredL1        0.18499925   0.06565456 2.81777  0.013693 * BoBCL1       -0.07682710   0.03406916 -2.25503  0.040666 * --- Signif. codes: 0 â***â 0.001 â**â 0.01 â*â 0.05 â.â 0.1 â â 1 Residual standard error: 54.44479 on 14 degrees of freedom  (3 observations deleted due to missingness) Multiple R-squared: 0.9324472,   Adjusted R-squared: 0.903496 F-statistic: 32.20757 on 6 and 14 DF, p-value: 2.046024e-07 Without NAs > ydat3<-na.omit(ydat2) > regCred<-lm(DCred1~DCred2+DCred3+DBoBC2+DBoBC3+CredL1+BoBCL1,data=ydat3) > summary(regCred) Call: lm(formula = DCred1 ~ DCred2 + DCred3 + DBoBC2 + DBoBC3 + CredL1 +    BoBCL1, data = ydat3) Residuals:        Min         1Q     Median         3Q        Max -124.988463 -33.133975   7.971083  23.607953  76.813601 Coefficients:                 Estimate   Std. Error t value  Pr(>|t|)   (Intercept) -538.61375718 205.91179535 -2.61575  0.020344 * DCred2        0.96401908   0.15623660 6.17025 2.4337e-05 *** DCred3       -0.25720355   0.08983607 -2.86303  0.012524 * DBoBC2       -0.11222347   0.07828182 -1.43358  0.173646   DBoBC3        0.04564621   0.03825169 1.19331  0.252578   CredL1        0.18499925   0.06565456 2.81777  0.013693 * BoBCL1       -0.07682710   0.03406916 -2.25503  0.040666 * --- Signif. codes: 0 â***â 0.001 â**â 0.01 â*â 0.05 â.â 0.1 â â 1 Residual standard error: 54.44479 on 14 degrees of freedom Multiple R-squared: 0.9324472,   Adjusted R-squared: 0.903496 F-statistic: 32.20757 on 6 and 14 DF, p-value: 2.046024e- #Same result Not sure what you meant by ("This is good, but couldn't I code the process for my 15 variable model?") A.K. ________________________________ Cc: R help <r-help@r-project.org> Sent: Monday, July 2, 2012 5:13 AM Subject: Re: [R]  Adjusting length of series Hi David and AK, I have been trying to implement your suggestions since yesterday, but I encountered some challenges. As for David's suggestions, I could only implement it after some modifications. Using an abridged version of my data, I dpud my dataset and then show my steps below. > dput(ydata) structure(c(68.1000000000004, -34.8000000000002, 90.3999999999996, 54.6000000000004, -172.3, 51.8000000000002, 175, 79.8000000000002, -35.7000000000007, 130.5, 116.8, -67.5, 164.5, 514.8, -326.1, 98.4000000000005, 160.2, 53.1999999999998, 283.6, -111.6, 127.8, -17.3000000000002, 286.3, NA, NA, -102.900000000001, 125.2, -35.7999999999993, -226.900000000001, 224.1, 123.2, -95.1999999999998, -115.500000000001, 166.200000000001, -13.6999999999998, -184.3, 232, 350.3, -840.900000000001, 424.500000000001, 61.7999999999993, -107, 230.400000000001, -395.200000000001, 239.400000000001, -145.1, 303.6, NA, NA, NA, 228.1, -160.999999999999, -191.100000000001, 451.000000000001, -100.900000000001, -218.4, -20.3000000000011, 281.700000000002, -179.900000000001, -170.6, 416.3, 118.3, -1191.2, 1265.4, -362.700000000002, -168.799999999999, 337.400000000001, -625.600000000001, 634.600000000001, -384.500000000001, 448.700000000001, NA, NA, -164.457840999999, 17.0793539999995, 95.9767880000009, 680.238166999999, -491.348690999999, -274.694009, -256.332907, 469.62296, -146.431891, -41.0772019999995, -106.970104, 757.688263999999, -1689.214533, 2320.098952, -1446.97942, 516.384521, -375.277650999999, 293.867029999999, 417.845195, 278.198807, -968.592033999999, -314.195986, NA, NA, NA, 181.537194999999, 78.8974340000013, 584.261378999998, -1171.586858, 216.654681999999, 18.3611019999998, 725.955867, -616.054851, 105.354689000001, -65.8929020000005, 864.658367999999, -2446.902797, 4009.313485, -3767.078372, 1963.363941, -891.662171999999, 669.144680999999, 123.978165, -139.646388, -1246.790841, 654.396048, NA, 4937, 5005.1, 4970.3, 5060.7, 5115.3, 4943, 4994.8, 5169.8, 5249.6, 5213.9, 5344.4, 5461.2, 5393.7, 5558.2, 6073, 5746.9, 5845.3, 6005.5, 6058.7, 6342.3, 6230.7, 6358.5, 6341.2, 6627.5, 4187.5, 4296.004835, 4240.051829, 4201.178177, 4258.281313, 4995.622616, 5241.615228, 5212.913831, 4927.879527, 5112.468183, 5150.624948, 5147.704511, 5037.81397, 5685.611693, 4644.194883, 5922.877025, 5754.579747, 6102.66699, 6075.476582, 6342.153204, 7026.675021, 7989.395645, 7983.524235, 7663.456839), .Dim = c(24L, 7L), .Dimnames = list(    NULL, c("DCred1", "DCred2", "DCred3", "DBoBC2", "DBoBC3",    "CredL1", "BoBCL1")), .Tsp = c(2001.08333333333, 2003, 12 ), class = c("mts", "ts")) NB: the NAs in the dataset emanated from lagging or differencing the series David's suggestion  df<-data.frame(DCred1,DCred2,DCred3,DBoBC2,DBoBC3,CredL1,BoBCL1) Error in data.frame(DCred1, DCred2, DCred3, DBoBC2, DBoBC3, CredL1, BoBCL1) :  arguments imply differing number of rows: 23, 22, 21, 24 So I modified as follows: length(DCred3) # finding the minimum length of various series [1] 21 # Then dataframe construction dframe<- data.frame(Dcre1=DCred1[1:21],Dcre2=DCred2[1:21],Dcre3=DCred3[1:21], + Dbobc2=DBoBC2[1:21],Dbobc3=DBoBC3[1:21],CredL=CredL1[1:21],BoBCL=BoBCL1[1:21]) # Then estimated regression > regCred<- lm(Dcre1~Dcre2+Dcre3+Dbobc2+Dbobc3+CredL+BoBCL, data=dframe) > summary(regCred) # Worked well as shown by results below Call: lm(formula = Dcre1 ~ Dcre2 + Dcre3 + Dbobc2 + Dbobc3 + CredL +    BoBCL, data = dframe) Residuals:    Min     1Q Median     3Q    Max -69.516 -27.695 -8.085 13.851 107.276 Coefficients:             Estimate Std. Error t value Pr(>|t|)   (Intercept) 159.32304 157.15209  1.014 0.327873   Dcre2       -0.75527   0.17262 -4.375 0.000634 *** Dcre3       -0.21006   0.08656 -2.427 0.029329 * Dbobc2       0.05111   0.06565  0.779 0.449197   Dbobc3       0.03106   0.03510  0.885 0.391108   CredL       -0.10967   0.04933 -2.223 0.043177 * BoBCL        0.09756   0.03097  3.150 0.007087 ** --- Signif. codes: 0 â***â 0.001 â**â 0.01 â*â 0.05 â.â 0.1 â â 1 Residual standard error: 52.3 on 14 degrees of freedom Multiple R-squared: 0.9331,    Adjusted R-squared: 0.9044 F-statistic: 32.55 on 6 and 14 DF, p-value: 1.911e-07 This is good, but couldn't I code the process for my 15 variable model? Perhaps that is where the use of Dcr<- lapply(..., function(x) ...) comes in? AK, if you spare some minutes, please use my dput data to illustrate the suggestion you made, I searched the lapply function (using ??lapply) but could not get a handle of how to use it in my case. My dput data is as shown below.         DCred1 DCred2 DCred3     DBoBC2     DBoBC3 CredL1  BoBCL1 Feb 2001  68.1    NA     NA         NA         NA 4937.0 4187.500 Mar 2001 -34.8 -102.9     NA -164.45784         NA 5005.1 4296.005 Apr 2001  90.4 125.2  228.1   17.07935  181.53719 4970.3 4240.052 May 2001  54.6 -35.8 -161.0   95.97679   78.89743 5060.7 4201.178 Jun 2001 -172.3 -226.9 -191.1  680.23817  584.26138 5115.3 4258.281 Jul 2001  51.8 224.1  451.0 -491.34869 -1171.58686 4943.0 4995.623 Aug 2001 175.0 123.2 -100.9 -274.69401  216.65468 4994.8 5241.615 Sep 2001  79.8 -95.2 -218.4 -256.33291   18.36110 5169.8 5212.914 Oct 2001 -35.7 -115.5  -20.3  469.62296  725.95587 5249.6 4927.880 Nov 2001 130.5 166.2  281.7 -146.43189 -616.05485 5213.9 5112.468 Dec 2001 116.8 -13.7 -179.9  -41.07720  105.35469 5344.4 5150.625 Jan 2002 -67.5 -184.3 -170.6 -106.97010  -65.89290 5461.2 5147.705 Feb 2002 164.5 232.0  416.3  757.68826  864.65837 5393.7 5037.814 Mar 2002 514.8 350.3  118.3 -1689.21453 -2446.90280 5558.2 5685.612 Apr 2002 -326.1 -840.9 -1191.2 2320.09895 4009.31348 6073.0 4644.195 May 2002  98.4 424.5 1265.4 -1446.97942 -3767.07837 5746.9 5922.877 Jun 2002 160.2  61.8 -362.7  516.38452 1963.36394 5845.3 5754.580 Jul 2002  53.2 -107.0 -168.8 -375.27765 -891.66217 6005.5 6102.667 Aug 2002 283.6 230.4  337.4  293.86703  669.14468 6058.7 6075.477 Sep 2002 -111.6 -395.2 -625.6  417.84519  123.97817 6342.3 6342.153 Oct 2002 127.8 239.4  634.6  278.19881 -139.64639 6230.7 7026.675 Nov 2002 -17.3 -145.1 -384.5 -968.59203 -1246.79084 6358.5 7989.396 Dec 2002 286.3 303.6  448.7 -314.19599  654.39605 6341.2 7983.524 Jan 2003    NA    NA     NA         NA         NA 6627.5 7663.457 Thanks kindly. Lexi       [[alternative HTML version deleted]]
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