Spotting missing dates in time series data

[Kartikeya Bhatotia]

Hey all

I have time series of 20 years (2000-2019) a total of 6995 days. Some of the dates have been skipped in the middle and I want a list of these dates that have been skipped.

Here's the dataset, can't post all of it of course but the variables range from a20000102 to a20190629 (aYYYYMMDD)

* Example generated by -dataex-. To install: ssc install dataex
clear
input str6(date v2) float(a20000102 a20000103 a20000104 a20000105 a20000106 a20000107 a20000108 a20000109 a20000110 a20000111 a20000112 a20000113 a20000114 a20000115 a20000116 a20000117 a20000118 a20000119 a20000120 a20000121 a20000122 a20000123)
"AK273"  "AK273"   6.062607  5.458793  5.365584  6.482221  5.360861  4.566375     5.949  5.409347  4.766882  4.791332   8.09921  7.406796  6.648993  4.527711  4.799754  4.993483  3.851703  4.280337  6.167405  5.241677  5.228392  4.141677
"AL684"  "AL684"   2.791116  3.393623  3.486095  3.445409  3.757444 4.2685995 3.4170146 4.0226884  5.271491  5.291882  5.843767  5.816685    6.0745   6.46742   7.64436  5.362897   4.95953  3.391902  4.566545 4.2406106   4.11853  5.162059
"AM222"  "AM222"    6.96068  7.807065  7.209305  6.302221  6.773685  4.691213  5.933544   6.52927  5.921649  6.078493  8.207117  9.007261  7.475771  6.648854  7.262829  7.022714  3.893412  6.415088  6.389864  5.989251  5.886443  6.533039
"AM3633" "AM3633"  2.337495  2.449916 2.0699334  3.068688 2.6684136  2.904725   2.77144 2.9174654  2.967303  2.886481 2.1572046 2.2569435  2.937875  2.386779  2.618194  2.988539 2.2573984 3.1672695 4.3362036 2.5867705  2.883962 2.5358706
"AM3653" "AM3653"  2.546324  2.647999  2.354698   3.38892  2.859582  2.746597  2.862608  2.642571 3.3131514  2.928863 2.5843515  2.619558 2.6496625 2.2966492 2.5017455  3.066389  2.493384  3.193906   3.86474  2.958217  2.542459 2.8154905
"AM3655" "AM3655" 2.6306155  2.611327 2.4145775 3.3577764  2.868613 2.6047254  2.816084  2.445143  3.311947 2.9032476   2.56306  2.618354  2.493231  2.103546 2.7279086  3.116417 2.6651955  3.056358 3.7804484  3.059093 2.5566354  3.017242
"AM774"  "AM774"   3.387514  3.180691  2.782931  2.828851  3.453856 4.4318724   2.55772 2.5034375  2.433736 1.6566373  2.527613 3.6593926  3.162584 2.6323705  3.207574 4.3348026  4.034071  3.276556  2.723535 2.1090317  2.298532 2.0038846
"AM853"  "AM853"  3.0811205  3.270701  2.772941  2.538841  3.301109  4.178226 2.1140635 2.9034376 2.1164536 1.5993377 2.4376025  3.606645  2.840706 2.6423604  3.038443   4.11752  3.680425  2.875657  2.511747 2.1671734  2.531299 1.7129754
"AN249"  "AN249"   7.003537  7.907065  7.209305  5.702221  6.302257  4.804725  6.004973  6.800699  6.507363  7.307065  9.107118  9.507261  8.704342  6.503546  6.505686  6.008429  4.307698  6.300802  7.204149  5.503537  6.100729  6.404468
"AN3121" "AN3121"   2.93701  3.532763  3.972713 2.9728014 3.2690165  3.426092 1.5075456 2.3769011 1.9099482 1.7011757 2.4349835  3.431314  2.382374 3.7674186  2.662601 2.7350614  3.053947 2.1451085  2.629098 1.4021405 4.6560802  2.433318
"AN3148" "AN3148"  2.258206  2.655404 3.0694525 2.2880433 2.8860204 2.7332556 1.7803392  2.048825  2.568537 1.5745077   2.88898  2.499222  3.195486 3.9675105 2.6201906 2.6244936  2.866738 3.6199906  2.936619   2.30839   3.96111 2.3852296
"AR872"  "AR872"   3.186171  3.307065  2.809305 2.6209955 3.4788866 4.2240176 2.1827505  2.844178  2.066622  1.981139 2.5227084  3.725164  3.337676 2.7245154 3.2983756 4.1269474  3.726216  2.921448 2.3582263 2.4998336 2.3669896  1.722403
"AS3212" "AS3212"  3.339765  2.952444  2.766484  3.465492 2.8019464   2.96376  2.393331  2.672133   3.00101 2.5602746  3.008168  3.285733   3.06201  3.996928 2.9658854  3.058261  2.682752 2.7795954  4.263495  3.864228  4.938723  3.443522
"AS3627" "AS3627"  2.745426 2.5680406 2.2897928  3.121733 2.6827445 2.5242374  2.343997 2.7616744 2.8398604 2.9032476 2.4014375 2.3233874  2.965318 2.1840336  2.562403 2.9053054  2.548483 2.7203145  4.724622 2.6425614 2.1401043  2.963313
"AS773"  "AS773"   3.468393 3.1537316 2.7959716  2.869144  3.507775 4.4588323  2.638306  2.410104  2.474029 1.6705567  2.527906  3.673312  3.257676   2.61933  3.275413 4.3617625  4.101031  3.316263  2.709323  2.163537 2.2440267 2.0305512
"AS952"  "AS952"  3.4872954  4.007065  3.081527 2.7527206  4.902256   4.01661 2.2049727   1.86181 2.2240295  3.851509   3.00419  3.378825  5.193231  2.579701 4.0131903   4.04975  3.852142  3.389691  3.963782  3.014648 2.4170504  3.176107
"AS953"  "AS953"   3.403962  4.007065  3.109305  2.808276  4.902256  3.905499 2.2049727 2.0006988 2.3073628  3.907065   3.00419 3.4066024  5.304342 2.6074786  3.902079 4.1053057  3.907698 3.5008025 4.1026707 2.9085195 2.3059392 3.2038846
"AT3120" "AT3120"  2.629411 2.7504215  2.999981  2.925992 3.0019464 1.6804838 1.5807303 2.1920743 1.5502363  1.698673  2.201239 2.8851166 3.5838296  3.171584  4.136122  3.383161 4.1254134 4.0942755  3.900806  2.893308 2.6742375   3.75202
"AT3140" "AT3140" 2.1276069 2.2317297  2.619046  2.114738  2.910436 2.0579455 1.5439804 1.7975076 2.2853708  1.274625 2.6946735  2.564243  3.144557  3.297086  2.801184  2.898871  3.505821  3.960856  3.363797  2.453738 2.3915906  2.960589
"AT3160" "AT3160"  3.366371   3.40451  3.887772   3.16964 3.4139354   3.99674 2.5134425   2.97862  2.539696  2.746539  3.026781  3.685863 2.2628727 4.1606474   3.40288  3.492701 3.2971654 2.6887586 3.6110504  2.695018  5.499506  3.065255
"AU3155" "AU3155"  4.407792  4.404602  4.730487  4.108709   4.02738  5.151805  3.282881  3.565507   2.45988  3.307432  3.265654   4.36624  2.746841  4.252314  3.595023  4.585714  4.580911  2.888113  4.855601  3.695712  6.071282  4.427506
"AU945"  "AU945"   3.532595 3.5271504  2.614433  2.819571  3.934869 4.4512253  2.335742  2.342754 1.9603543  3.174586  2.705899 3.8374145 4.5517783 2.6862085  4.198233  4.357574  3.789322  2.919606  3.207799  3.254392  2.805939 2.7320895
"Ab141"  "Ab141"   3.396108  2.575306  2.774761  3.563423  3.601141  2.900047  2.635458  2.648323  3.335837  3.802386   3.97203  3.441764  5.008436  5.107639  6.035931 3.7310364  4.103019  2.863218  3.406764  3.068874 3.3013315   3.76938
"Ab153"  "Ab153"  3.2686985  2.629836  2.817231  3.478484 3.4616716  2.581209  2.592988 2.1811566 2.8686705  3.250281  3.462394  2.974598   4.60786  4.695003  5.592885 3.5002415  3.550914 2.7782786 3.0182486  2.729738 3.3013315  3.271804
"Ab1631" "Ab1631" 1.9801526  2.462476 2.2687407  2.443774  3.011903 1.7688103 1.3495615  1.795158 2.8767674 2.1906865 2.3217838  2.403875 2.0293958  3.771365 4.3836083  3.343061 4.1076975 2.1592438  3.558082  2.136132 2.0505278 2.4390996
"Ab1777" "Ab1777"  5.035864  4.935364  3.400547  5.208103  4.942437  4.303741  5.669254  4.169216  3.998528   5.45942   6.56082  5.686327  4.564618   7.47197  8.932393  8.313482  6.160126  4.397008   6.06293  7.686128  7.240548  3.378891
"Ab3372" "Ab3372" 2.2081523 2.8002155  1.332697 2.2314517 4.3850236  1.933956  1.378258 4.2104425 2.5129645  3.284153  5.868143   8.64162  4.660159  5.612491  5.363446  4.590139 4.1600313  4.822854  3.385748 3.2065485 4.0128746  3.285714
"Ab8"    "Ab8"    1.2083932 2.2046177 1.8082228  1.500941  1.707485 2.3034425 2.1049247  2.407863 2.3073628 1.7007848 1.6071174  1.507261 2.0047204 2.0063155 2.3076246 2.8053055 1.9070196 2.0008025  3.501659  2.904591 2.9022965  2.502942
"Ac1143" "Ac1143"  4.509341  3.834136  4.291833  4.320554  3.834242  3.777198  3.777966  4.051071  5.128893  5.897857  4.099637  4.219495  4.443521  4.889963  4.702073  6.150735  5.667278  3.930389  3.035372  5.496901  5.006125  2.378969
"Ac1152" "Ac1152"  4.664915  4.861139  3.892997  4.821735  3.990083   4.92122   4.39164  4.125916  4.669972  4.269673  3.538422  2.960397  3.273038  4.472241  3.864036  3.999218  4.225417  3.188291  4.399268  5.197875  5.465243  4.668399
"Ac2647" "Ac2647"  3.102789  3.114103  2.947721  3.674362  3.333635 3.0717745  2.231625  2.440445 2.8357334  3.899903  4.848991 3.5676715  2.843932  3.937694 4.0441027 4.4407864  3.673295 2.8043215 4.6748114 4.5063076  2.405939  2.465368
"Ad1187" "Ad1187" 4.5121846 4.1587462 4.2544594 4.5062685  3.827138 4.0272083  3.893598 4.5893245  5.071344  5.316307 4.4315248 4.6185465 4.7531576  4.900408  4.774887  5.554121  4.541347  3.034452   4.87526  5.643772  5.716497   5.26834
"Ad1200" "Ad1200"  4.070087  2.967929  3.824453  3.702477  3.522465  3.887299  3.376097  3.505548  4.238023   5.51722  4.468952  4.742071  4.235907  4.695444  5.375338  5.856875  5.123841  3.100802  3.021378  5.387688  3.210305   3.06234
"Ad1663" "Ad1663"  2.303537 2.8002155  2.503373  3.300941  5.501946 4.0047255 2.1049728 4.5138197  2.507363  5.001076  8.410575  2.603875  5.004342 4.7073627   5.00242       5.3  7.007698  6.700802  7.502671 3.7006924 3.7022965 3.9038844
"Ad1965" "Ad1965" 1.3853798  2.657397 1.5990366 2.0057292 4.7041144 1.9236015 2.3187459 4.6643844  2.507411  5.101618  5.450684  7.084496  4.382391 4.5721326  4.724526   5.36306  5.681128  4.963404  4.217576 4.1529956  4.158936   1.96215
"Ad3290" "Ad3290"  4.703537  3.202514  4.603467  4.702221  4.401947  2.505499  5.003766  6.505548   6.70101   7.00389  9.810575  5.607261  4.904477  3.708449  3.903955  3.207437  5.301728  4.305295  5.202671  6.401933  4.604027  5.402338
"Ad414"  "Ad414"   4.994871  4.525247  5.604759  5.181003  4.379529  5.878226  5.605049  6.286547  4.678282  5.799338  5.701438  4.122057  2.563811  2.419633  1.797282  4.859851  3.980425  5.675657  3.419841  3.381864   3.25718  2.642154
"Ad968"  "Ad968"   2.492534  2.636319  2.754781  2.570656   3.23805  3.128377  2.212245  2.279828  2.982687  3.993818  3.200445  2.278161   3.16152  2.500206   3.76182  3.598039   3.37575  2.938563  2.810982  1.840894  1.790355  2.627877
"Af2194" "Af2194"   3.21073  2.942651  3.294151  3.685948  3.997007  3.979691  3.297239  3.305095  3.796626  5.488062  3.935507  2.543053  3.402242  1.845312  4.994228   4.52736  4.063451  2.618337  2.177739  2.045455  2.458936  4.701316
"Ag1497" "Ag1497"  3.149676  3.207065 4.1018763  4.808506  5.365685  3.403011 2.2832427 3.5721276 2.2888849 2.0104933  3.129333  2.813018  4.916914   1.55205  5.208543 4.2424483  4.140269  4.208802  4.599242 2.8645196 3.4944744  3.725039
"Ag2496" "Ag2496"  3.715078  2.674933  3.151574  4.261437  2.831222  2.269578  2.562057  4.149851  2.222001  4.188729    7.0159  4.599249   3.95398  5.188894  6.430186  5.047104  3.517497  3.807582  4.373087  4.697028  2.821905  3.315743
"Ag35"   "Ag35"   1.8232068  2.050451 1.8165562  1.398898 1.6908184 2.4034424  1.913258 1.1328632 2.5740294 1.9750953 2.2737842 1.5734744  3.046387 2.5577126 2.5889275  2.545833 2.4869545  1.806626 2.2151706  1.893766  2.118963 1.7904418
"Ag3919" "Ag3919"   .970037 2.2618594 2.8266604 3.6257646  5.001946 2.7814376  2.603766  2.900163  2.615582  4.709295   4.57815  5.030096  3.512696 4.4457192  5.863071         5  5.547996  5.739159  6.019023  3.831807 3.3022964  3.327172
"Ag3925" "Ag3925" 1.0083932 2.3002155  2.903373  3.702477  5.001946  2.704725  2.603766   2.91382  2.807363  4.901076 4.5014377  5.106808  3.704477  4.407363  5.901427         5   5.50964  5.700802  5.903955 3.9085195 3.3022964 3.4038844
"Ag3931" "Ag3931" 1.0083932 2.3002155  2.903373  3.702477  5.001946  2.704725  2.603766   2.91382  2.807363  4.901076 4.5014377  5.106808  3.704477  4.407363  5.901427         5   5.50964  5.700802  5.903955 3.9085195 3.3022964 3.4038844
"Ag3934" "Ag3934" 1.0083932 2.3002155  2.903373  3.702477  5.001946  2.704725  2.603766   2.91382  2.807363  4.901076 4.5014377  5.106808  3.704477  4.407363  5.901427         5   5.50964  5.700802  5.903955 3.9085195 3.3022964 3.4038844
"Ah1619" "Ah1619" 2.3188558 2.6347244  2.464624  2.791255 2.8469374  1.892733  1.180724 1.7204587  2.666967  2.230863 2.0971823 2.2868538 2.0430183  3.454933  4.501827  3.406301 4.0076976  1.841228 3.5728836  2.423413 1.7889178 2.3018756
"Ah2742" "Ah2742" 2.6829965  2.666382 2.4217525  2.665922 3.7969975  2.880964  1.893406 1.6311024  2.466667 2.1893125  2.119397  1.941188 1.7771387 3.5032375 2.5560985  2.883924  3.441801 2.7854755  2.276336 3.8699894  2.846281  1.832452
"Ah2821" "Ah2821"  3.795789  3.514807   3.40517  3.117367  4.192855  3.895634  3.504973  3.100163  3.325545  3.525247  3.864875  2.394784  4.114244  3.124497  3.920261  4.214396  4.112712  2.482621  1.802656   3.90852  2.993543  3.377195
"Ah2847" "Ah2847"   3.22397  2.872242  2.984968  3.386692    3.9326  3.674846  3.237315   3.46951   3.81776  5.561713  4.449268   2.78344  3.238672  3.003546  3.813655  3.416026  3.010378  3.733466   3.17721  2.880511  3.182701  4.499759
"Ah3513" "Ah3513"  4.887694   4.03927   3.41376 3.8572965  3.600529 4.1304126  4.317204   5.88231  3.405785  3.264995  6.877354  6.752759  5.199792 4.7046094   7.88465  5.737398  5.218584  5.095968  2.942102  3.932682 3.7311356  3.614027
"Ai2790" "Ai2790"  3.803962  3.707065  4.100881  4.200882  4.101646  4.502628  4.103814   3.50144  3.202597  3.900785  4.507117  4.507261  4.404342  4.206316  3.905686  3.408429  3.605657  3.500803  4.102671  3.703962  4.700728  4.005791
"Ai3055" "Ai3055" 2.3039622 2.2002156 2.2033727 2.2438874 2.1439233  2.546392 2.3049726 3.2423656  3.007363  2.465398 2.6071174  3.148928 3.7043424  2.603546 2.7597606 2.9053054 2.2493644 3.4841356  3.661004  2.087295  3.442395 3.2044675
"Ai3056" "Ai3056" 2.3039622 2.2002156 2.2033727  2.202221 2.1022568  2.504725 2.3049726  3.200699  3.007363  2.507065 2.6071174  3.107261 3.7043424  2.603546 2.8014274 2.9053054 2.2076976 3.4008024 3.7026706 2.0039618  3.400729 3.2044675
"Ai3057" "Ai3057" 2.3039622 2.2002156 2.2033727 2.2355542   2.13559 2.5380585 2.3049726  3.234032  3.007363 2.4737315 2.6071174 3.1405945 3.7043424  2.603546  2.768094 2.9053054  2.241031  3.467469  3.669337 2.0706284  3.434062 3.2044675
"Ai3059" "Ai3059" 2.3083525 2.2002156 2.2033727 2.3022208 2.2022567 2.6047254 2.3049726  3.300699  3.007363  2.407065 2.6071174  3.207261 3.7043424  2.603546 2.7014275 2.9053054 2.3076978 3.6008024  3.602671 2.2039616 3.5007286 3.2044675
"Ai3060" "Ai3060" 2.3083525 2.2002156 2.2033727 2.3022208 2.2022567 2.6047254 2.3049726  3.300699  3.007363  2.407065 2.6071174  3.207261 3.7043424  2.603546 2.7014275 2.9053054 2.3076978 3.6008024  3.602671 2.2039616 3.5007286 3.2044675
"Ai3061" "Ai3061" 2.3083525 2.2002156 2.2033727 2.3022208 2.2022567 2.6047254 2.3049726  3.300699  3.007363  2.407065 2.6071174  3.207261 3.7043424  2.603546 2.7014275 2.9053054 2.3076978 3.6008024  3.602671 2.2039616 3.5007286 3.2044675
"Ai3064" "Ai3064" 2.3083525 2.2002156 2.2033727 2.3022208 2.2022567 2.6047254 2.3049726  3.300699  3.007363  2.407065 2.6071174  3.207261 3.7043424  2.603546 2.7014275 2.9053054 2.3076978 3.6008024  3.602671 2.2039616 3.5007286 3.2044675
"Ai3065" "Ai3065" 2.3083525 2.2002156 2.2033727 2.3022208 2.2022567 2.6047254 2.3049726  3.300699  3.007363  2.407065 2.6071174  3.207261 3.7043424  2.603546 2.7014275 2.9053054 2.3076978 3.6008024  3.602671 2.2039616 3.5007286 3.2044675
"Ai3066" "Ai3066" 2.3806288  2.273919 2.2033727 2.3022208 2.2022567  2.607688 2.3049726  3.300699    3.0044 2.4769514 2.6071174  3.283928  3.707305 2.6772494 2.7014275 2.9053054 2.3106606  3.751173 3.5997076 2.2835913  3.651099 3.2074306
"Ai3067" "Ai3067" 2.3083525 2.2002156 2.2033727 2.3022208 2.2022567 2.6047254 2.3049726  3.300699  3.007363  2.407065 2.6071174  3.207261 3.7043424  2.603546 2.7014275 2.9053054 2.3076978 3.6008024  3.602671 2.2039616 3.5007286 3.2044675
"Aj3270" "Aj3270"  3.125399  3.428556  2.864195  3.869023  3.656602  2.011112  5.628867  6.481836  6.030901   6.83304  9.155919  5.035601  4.058972  3.807768  3.271566  3.203885  4.298489  3.621489   4.23182  6.179261  5.248723  3.470354
"Aj3488" "Aj3488" 3.6238866 3.2557156 2.7051704  3.519271   3.38528  2.872166  3.504973  5.384032 4.1557846  4.879435  6.157117  6.207261  6.004343 4.3406963  5.584761 3.9002416  3.533533  4.287233 2.3026707 2.1535373  4.267998 3.1044674
"Aj3494" "Aj3494"   3.70722  3.505716   2.70517  3.602604  3.301946  2.705499  3.504973  5.300699  4.405785  4.712768  5.907117  5.707261  5.504342  4.007363  5.501428  3.900242    3.7002    4.2039  2.302671  1.903537  4.101331  3.104467
"Aj4108" "Aj4108"  2.551145  2.449697  2.750854  3.249826  3.990989  3.257542 2.5106065  2.947882  2.295376   1.60389  3.301239 2.1038752 3.9519036 2.9119494 4.7508416 4.5053053 4.4133315  5.206436  5.008305  3.055703 2.8956976 1.9988337
"Ak1591" "Ak1591"  2.643539 2.8986056  2.988761  3.603127    2.7382 1.5619944  .8641872 2.0043242 2.2312298  2.085366 2.7201085 2.2120948  2.957525 3.1519184  4.903327  3.677009  3.520991  2.863642  3.631674  2.994776 2.7805614 3.8973694
"Ak1868" "Ak1868"  5.103962  4.307065  3.909305  3.808276  3.302257  3.305499  3.303814  3.000163  1.607363  3.307065  3.707117  4.507261  4.105153  4.407363  5.902079  5.908429   5.50702  4.500803  4.102656  3.503962  3.702634   2.40315
"Ak2630" "Ak2630"  4.228887  3.826462  3.321767  3.857824 3.3388395  3.345298  3.096377  2.994334 1.3949063 3.6137726  4.503801  4.647261 3.6957996   3.86097  4.730019  5.434761  4.961994  4.391355 4.2014647  5.316625  4.703539  2.536784
"Ak2655" "Ak2655" 2.8234744  3.176701  2.867435 3.5688455  3.344127  3.226434  2.389945  2.829531  3.204698  4.776483  4.832323  3.527383  3.635034 3.8731856 4.0032473 4.2790136 3.8108814  3.203038 4.6026707 4.7659535  2.705683 2.5691285
"Ak2674" "Ak2674"  2.631574  2.760474  2.799355 3.3070326  3.480615  3.283857  2.453268   2.85505 3.1879005 4.7672453   4.92351  3.428903 2.8571975 4.1441264   4.18106  4.121364  3.992343  3.052046  4.579785  4.615653  2.676764 2.7337875
"Ak2694" "Ak2694"  2.603962  2.702514  2.809305  3.308276 3.5022566  3.305499  2.503766 2.9055474  3.200836  4.901076  4.910575  3.407261  2.800481 4.2063155 4.2056866  4.108429 4.0070195 3.1008024 4.6026707 4.6039615  2.702634  2.802942
"Ak2750" "Ak2750" 2.8627784   2.72815  2.752955  2.857351  2.777469  2.794278  2.600978  2.573776 2.0978038  2.570721 3.1290655  2.479148  2.392012  2.403669  2.744249  3.315334  3.311082 2.7397666 3.0455806  4.114196 4.0079365  2.611249
"Ak2885" "Ak2885"  3.363519  3.158123  3.293006  3.623967  3.984404  3.785394  3.220501  3.310499  3.718071  5.255372   4.08405  1.584062   3.03548  1.616871  5.149658  4.529216  4.069217  2.795946  1.968798    2.1987  3.036696  4.569643
"Ak29"   "Ak29"   1.8245957 2.1601732 1.9526672  1.562787 1.8297073  2.447887  2.127147 1.6411966 2.5851405  1.975095 2.2071173  1.607261  2.949165 2.6591015 2.5014274 2.6053054  2.503621 2.0802374  2.401659 2.2268133 2.3356297 2.0927734
"Ak4005" "Ak4005" 2.2817767 2.3820038 2.2904587  2.844605  4.074132  3.077242  2.645867 2.6110535 1.6566316  3.341638  4.806508 4.3029566  3.049855  5.503998   6.06591  5.053131  6.035181  6.949471   6.32614  3.457231 3.2254755  2.449689
"Ak4012" "Ak4012"  2.833295  3.104542 2.9776895  3.567632 3.7995245  3.404725 2.1367989  2.957529  2.394776 1.6952813 2.9214575  2.731398  3.647512  3.001944  5.498335  5.292683 3.5951295   5.17348  4.209228  3.213984 2.2693272 1.9777156
"Al1046" "Al1046"  3.236218  4.150637   3.12833   3.37246  4.838203  3.360103  2.644096  3.191424  3.968071  5.172663  3.619466  3.509789  3.551095  4.007774   2.90733  4.046621  5.175151    4.2492  2.907595  5.820423  3.962543  2.494855
"Al1184" "Al1184"  3.706906  2.820381  3.501699  3.747894  3.571611  3.812772  3.397309  3.316291  3.986041   5.24161  4.374793  4.522183  4.833043  5.755391  4.774897  5.522991  4.999598  2.841298  2.738292  5.871601   3.96882  2.546856
"Al1203" "Al1203"  4.103261  3.119527  4.005614  3.853864  3.476244  3.977804  3.463433  3.552717  4.416692  5.455682   4.36872  4.663582  4.136774  4.555841  5.512064  6.006637  5.250761  3.365397  3.153614  5.411791  3.430664   3.02131
"Al1211" "Al1211"  5.016105  4.162156  4.591364  4.514169  3.773464  3.896765  4.163631  4.557664  5.143806  5.498109  4.795232  4.770918  4.945373  5.354378  5.890607  6.726947  5.547996  4.082394  3.615482  4.701066  4.839972  2.954016
"Al1276" "Al1276"  5.003537  3.502514  3.403373  3.802221 4.4011087  3.804725  3.903766 3.6052825  3.607363  4.407065 3.5071175  3.407243  4.004342  4.403546 3.7024205  4.907437  6.901728  5.402732 4.4021716  4.001933 3.7022965 3.0038846
"Al1279" "Al1279"  5.003537  3.502514  3.403373  3.802221 4.4011087  3.804725  3.903766 3.6052825  3.607363  4.407065 3.5071175  3.407243  4.004342  4.403546 3.7024205  4.907437  6.901728  5.402732 4.4021716  4.001933 3.7022965 3.0038846
"Al1396" "Al1396"  2.408393 4.1002154  3.203373  2.307602 4.2019463  3.804725 2.0024881  3.300699  2.902597  2.612768 3.8071175  3.107261  5.304342  3.603546  5.601428  6.905305 3.2076976 2.8024595 3.2026706  4.808519 4.7013316 4.5038843
"Al1456" "Al1456"  3.083962 3.7363446  2.985953   3.01857  4.380321  4.107951  2.324459 3.3910215  2.456791  2.912768  3.558085  2.784035  5.917245 2.7538686   4.95175  6.896918  3.557375  3.299512  3.672993 3.9517455  3.583267  3.698723
"Al1462" "Al1462"  2.426529 2.8316314  2.127709  2.282823  3.564383  3.698419  2.352929  2.800163 2.1554346  2.753033  2.952693 1.7842523  5.283103   2.46682  5.205619  6.298226   2.46699 2.3074396  2.407538   3.39613  2.990712  3.602591
"Al1734" "Al1734"  5.303962  4.507065  4.309305  4.508276  5.002257  5.705499  5.403814  4.700163   3.80101  4.012768  3.701239  3.903381       3.8  4.303546  4.601827  2.708429  4.107019  2.902399  3.905355   4.50852  5.002635   4.40315
"Al183"  "Al183"   2.575616  2.394013 1.9033726 2.1085203 2.0865088 2.1015756  1.811272  2.900699   2.82626  2.590649 2.2291646 2.2513556  3.613791  2.900396 3.2762306 2.9895575 2.7699025 2.0646641 3.5121195  2.160988 2.2353742  2.448562
"Al187"  "Al187"  2.4972415  2.392351 1.9033726 2.1853797 2.0022566 2.0047252 1.8049728   2.81181  3.007363  2.492137 2.4182284  2.518372 3.7043424  2.981324 3.1903164 2.9053054  2.763253  2.058015  3.513782 2.0574887 2.3229508 2.7155786
"Al2186" "Al2186"  3.336187   3.07715  3.364663  3.727934  3.966664   4.14288  3.378002  3.305633  3.786138   5.46911  4.080661  2.399431  3.042552  2.143888  4.826861  4.127699   3.62804  2.658067  2.232072  2.215775  2.765369  4.694068
"Al2494" "Al2494"  3.555294  2.903184 2.2889876  3.820313  1.922717  2.111529 2.2324572 4.2553053 2.1274633 4.4677014  7.073617  4.607931  3.587836      5.24  6.676373  5.487156 4.1184096  3.860769 3.5760374  4.559406  2.908047 3.0544314
"Al2591" "Al2591"  4.414598  3.884367  3.201523  3.998938  3.328067  3.165421  2.569054 2.5916026  1.430709   3.81173 4.5529017  4.823215 3.5276885  3.829143  5.468073  5.885991  5.119212  4.233876  3.845602  5.272574  4.355423  2.473835
"Al3428" "Al3428"  1.592937 2.9002156  2.661473 2.8436315  4.699898  2.211962  2.516291 3.4819765  2.817977  6.551169  4.377601 3.8889115 3.6332724  4.478886  5.357107 4.2402234 4.6484795  5.034136 4.0948496  4.324901 2.9793096  3.654933
"Al3437" "Al3437" 1.6083932 2.9002156 2.6605155   2.85962 4.7448034 2.1625872  2.503814 3.3852484  2.778791  6.586791  4.472866  3.978031 3.6908674 4.5045843  5.315713 4.3285713 4.7667828  5.086517  4.188385 4.3435497  3.005939 3.6616104
"Al359"  "Al359"  4.2047033  4.231509  4.539675  4.409017  3.843738  5.147721  5.234184  4.849375  3.866195   4.47954  5.225882 2.9572084 2.6333785 1.7021776  2.066865 4.3533335  3.491769 4.5503373 2.9142516  2.864591  2.086338  3.136161
"Al3725" "Al3725"  6.743428  6.257159  6.658111  6.352494  6.262912  4.479131  4.130656  4.348793  4.411219  5.296786  5.200947  4.587042  4.262812  5.109594  6.082954  7.063721  5.759105  4.712842  5.660972  5.158217  4.106739  6.020339
"Al377"  "Al377"   5.003962  5.207065   5.52469  5.015969  4.302257  6.413191  6.419198  5.329204  4.408702  5.123813   6.20913  3.603381  3.415866   2.82148  1.807625  4.707692   3.70702  5.010622  3.609351  4.112283  3.610327  3.998098
"Al3857" "Al3857"   1.60722  2.807274 2.3033726 3.2026045  5.401947  3.704725  2.403814   2.91382 2.2013335  4.501076  7.110575  2.606808  3.505153  5.007363  6.005686  5.807062   7.30964  6.900803  7.603954  3.800692 3.7022965 3.7038846
"Al3882" "Al3882" 1.6794817  2.845794  2.331833  2.959067 4.5900416  3.307446   2.71844   2.81382  2.009173  3.158312  5.670439 2.5579414  3.101621  5.363825  5.631196  5.512504  6.433208  6.797063  7.275723  3.055114  3.148555  3.066211
"Al400"  "Al400"   5.003962  5.107065  5.791123  5.290094  4.747711  6.869135  6.967451  5.777456  4.964646  5.572065  6.583256   4.14933  3.236845  2.824277  1.707625  4.436364  3.965364  5.366566  4.165295  4.386409  4.166271  3.723973
end

Any ideas? I guess I could retain only the first row, transpose the row into a column and then convert the column into a date variable but even then I don't know how to find the skipped dates?

[Ken Chui]

Is your first variable correct? The variable name says "Date" but the data in the first column do not look like date, but duplicates of ID.

[Kartikeya Bhatotia]

Is your first variable correct? The variable name says "Date" but the data in the first column do not look like date, but duplicates of ID.

Sorry for the confusion, yeah it's incorrectly named. Date is supposed to be the ID and v2 is the duplicate of ID

[Ken Chui]

It seems your data set is in a wide form. So, whoever skipped a point would have missing data. If that's the case, one way is to reshape it into long form, and then obtain a list of ID and date where the data point is missing. Your sample data above do not have missing, so this code will show nothing. Here is a modified one to show how it works:

* Example generated by -dataex-. To install: ssc install dataex
clear
input str6(date v2) float(a20000102 a20000103 a20000104 a20000105)
"AK273"  "AK273"   6.062607 5.458793  5.365584  6.482221
"AL684"  "AL684"   2.791116 3.393623  3.486095  3.445409
"AM222"  "AM222"    6.96068 7.807065  7.209305  6.302221
"AM3633" "AM3633"  2.337495 2.449916 2.0699334         .
"AM3653" "AM3653"  2.546324 2.647999  2.354698   3.38892
"AM3655" "AM3655" 2.6306155        . 2.4145775         .
"AM774"  "AM774"   3.387514 3.180691  2.782931  2.828851
"AM853"  "AM853"  3.0811205        .  2.772941  2.538841
"AN249"  "AN249"   7.003537 7.907065  7.209305  5.702221
"AN3121" "AN3121"   2.93701 3.532763  3.972713 2.9728014
end

drop date
reshape long a, i(v2) j(d1, string)
gen date = mdy(real(substr(d1,5,2)), real(substr(d1,7,2)), real(substr(d1,1,4)))
format date %td

list v2 date if a == .

Here is the result:

     +--------------------+
     |     v2        date |
     |--------------------|
 16. | AM3633   05jan2000 |
 22. | AM3655   03jan2000 |
 24. | AM3655   05jan2000 |
 30. |  AM853   03jan2000 |
     +--------------------+

[Kartikeya Bhatotia]

The problem is not that the dataset has missing values, it has missing variables altogether i.e let's say there are no values available for 05jan2000 for any of the IDs so the variable a20000105 will simply not be there.

[Ken Chui]

Then for this sample code, please use the original data featured in #1:

* Drop that duplicated ID
drop date
* Let's drop Jan 10th, Jan 17th, Jan 18th:
drop a20000110 a20000117 a20000118

reshape long a, i(v2) j(d1, string)
gen date = mdy(real(substr(d1,5,2)), real(substr(d1,7,2)), real(substr(d1,1,4)))
format date %td

* Retain only one set of dates from the first ID:
keep if v2 == "AK273"
save temp01, replace

* Create a full series from Jan 1st 2000 to Dec 31st 2019:
clear
set obs 7305
gen date = _n + 14609
format date %td

* Merge the avaiable data to it:
merge 1:1 date using temp01

list in 1/23, sepby(_merge)

Results below. Whichever got a "master only (1)" is a date that no data were merged (i.e. skipped):

     +-----------------------------------------------------------+
     |      date      v2         d1          a            _merge |
     |-----------------------------------------------------------|
  1. | 01jan2000                             .   master only (1) |
     |-----------------------------------------------------------|
  2. | 02jan2000   AK273   20000102   6.062607       matched (3) |
  3. | 03jan2000   AK273   20000103   5.458793       matched (3) |
  4. | 04jan2000   AK273   20000104   5.365584       matched (3) |
  5. | 05jan2000   AK273   20000105   6.482221       matched (3) |
  6. | 06jan2000   AK273   20000106   5.360861       matched (3) |
  7. | 07jan2000   AK273   20000107   4.566375       matched (3) |
  8. | 08jan2000   AK273   20000108      5.949       matched (3) |
  9. | 09jan2000   AK273   20000109   5.409347       matched (3) |
     |-----------------------------------------------------------|
 10. | 10jan2000                             .   master only (1) |
     |-----------------------------------------------------------|
 11. | 11jan2000   AK273   20000111   4.791332       matched (3) |
 12. | 12jan2000   AK273   20000112    8.09921       matched (3) |
 13. | 13jan2000   AK273   20000113   7.406796       matched (3) |
 14. | 14jan2000   AK273   20000114   6.648993       matched (3) |
 15. | 15jan2000   AK273   20000115   4.527711       matched (3) |
 16. | 16jan2000   AK273   20000116   4.799754       matched (3) |
     |-----------------------------------------------------------|
 17. | 17jan2000                             .   master only (1) |
 18. | 18jan2000                             .   master only (1) |
     |-----------------------------------------------------------|
 19. | 19jan2000   AK273   20000119   4.280337       matched (3) |
 20. | 20jan2000   AK273   20000120   6.167405       matched (3) |
 21. | 21jan2000   AK273   20000121   5.241677       matched (3) |
 22. | 22jan2000   AK273   20000122   5.228392       matched (3) |
 23. | 23jan2000   AK273   20000123   4.141677       matched (3) |
     +-----------------------------------------------------------+