Gerenciamento de Dados: codificando dados faltantes

Podemos verificar dados faltantes na coluna especie quando procuramos por valores vazios (''). No resultado gerado temos Frequency Missing = 117669. Para ignorar os dados faltantes podemos simplesmente trocar o EQ por NE no código abaixo, executado no SAS Studio.

libname mydata "<caminho do arquivo>" access=readonly;
DATA new; set mydata.lajeado;
label especie="Espécies de Peixe";
if especie EQ '';
PROC SORT; by especie;
proc freq; tables especie;
run;

The FREQ Procedure

Espécies de Peixe
especie	Frequency	Percent	Cumulative Frequency	Cumulative Percent
Frequency Missing = 117669

Com o novo código que ignora os dados faltantes temos o seguinte resultado, sem apresentar a mensagem Frequency Missing:

libname mydata "<caminho do arquivo>" access=readonly;
DATA new; set mydata.lajeado;
label especie="Espécies de Peixe";
if especie NE '';
PROC SORT; by especie;
proc freq; tables especie;
run;

The FREQ Procedure

Espécies de Peixe
especie	Frequency	Percent	Cumulative Frequency	Cumulative Percent
A.acutus	1	0.00	1	0.00
A.aguaboen	16	0.01	17	0.01
A.albater	3	0.00	20	0.01
A.albifron	1	0.00	21	0.01
A.argenteu	351	0.11	372	0.12
A.blax	162	0.05	534	0.17
A.brevis	3150	1.02	3684	1.19
A.diaphanu	6	0.00	3690	1.19
A.elachyle	11	0.00	3701	1.19
A.euryceph	335	0.11	4036	1.30
A.falcatus	59	0.02	4095	1.32
A.gigas	126	0.04	4221	1.36
A.goyacens	681	0.22	4902	1.58
A.halecinu	3772	1.22	8674	2.80
A.hypselon	22	0.01	8696	2.80
A.hystrix	29	0.01	8725	2.81
A.machrisi	87	0.03	8812	2.84
A.maculosu	1	0.00	8813	2.84
A.microlep	2871	0.93	11684	3.77
A.minutus	74	0.02	11758	3.79
A.normani	428	0.14	12186	3.93
A.nuchalis	22019	7.10	34205	11.02
A.ocellatu	1	0.00	34206	11.02
A.robertsi	5094	1.64	39300	12.66
A.stigmatu	3	0.00	39303	12.67
A.ternetzi	38	0.01	39341	12.68
A.tetramer	149	0.05	39490	12.73
A.tocantin	21	0.01	39511	12.73
A.ucayalen	479	0.15	39990	12.89
Aequidens	2	0.00	39992	12.89
Anchoviell	125	0.04	40117	12.93
Ancistrus3	51	0.02	40168	12.94
Ancistrus4	2	0.00	40170	12.94
Ancistrus5	27	0.01	40197	12.95
Ancistrus6	1	0.00	40198	12.95
Apionichth	1	0.00	40199	12.95
Aspidoras	206	0.07	40405	13.02
Auchenipte	30	0.01	40435	13.03
B.copei	51	0.02	40486	13.05
B.cupido	91	0.03	40577	13.08
B.cuvieri	5435	1.75	46012	14.83
B.falcatus	100	0.03	46112	14.86
B.filament	5	0.00	46117	14.86
B.fowleri	1654	0.53	47771	15.39
B.goulding	71	0.02	47842	15.42
B.longipin	595	0.19	48437	15.61
B.niveatus	215	0.07	48652	15.68
B.pinnicau	8	0.00	48660	15.68
B.velox	1873	0.60	50533	16.28
Batrachog1	383	0.12	50916	16.41
Batrachog2	7	0.00	50923	16.41
Brycon1	1490	0.48	52413	16.89
Brycon2	1052	0.34	53465	17.23
BryconopsB	463	0.15	53928	17.38
BryconopsC	36	0.01	53964	17.39
C.acutiros	5234	1.69	59198	19.08
C.adspersa	195	0.06	59393	19.14
C.anchoveo	32	0.01	59425	19.15
C.araguaie	626	0.20	60051	19.35
C.asellus	2263	0.73	62314	20.08
C.atrisign	78	0.03	62392	20.11
C.britskii	2626	0.85	65018	20.95
C.callicht	17	0.01	65035	20.96
C.cametana	42	0.01	65077	20.97
C.coecutie	653	0.21	65730	21.18
C.cracenti	212	0.07	65942	21.25
C.cyprinoi	1316	0.42	67258	21.67
C.dorsalis	653	0.21	67911	21.88
C.epakros	91	0.03	68002	21.91
C.festivus	2222	0.72	70224	22.63
C.figueire	4	0.00	70228	22.63
C.gibbus	1220	0.39	71448	23.02
C.goulding	48	0.02	71496	23.04
C.hauxwell	1478	0.48	72974	23.52
C.immacula	731	0.24	73705	23.75
C.inornata	4287	1.38	77992	25.13
C.johanna	1	0.00	77993	25.13
C.kelberi	17	0.01	78010	25.14
C.labrina	44	0.01	78054	25.15
C.labyrint	6472	2.09	84526	27.24
C.lepidota	113	0.04	84639	27.28
C.leticiae	107	0.03	84746	27.31
C.lugubris	477	0.15	85223	27.46
C.macropom	13	0.00	85236	27.47
C.menezesi	272	0.09	85508	27.56
C.mucipu	72	0.02	85580	27.58
C.piquiti	1951	0.63	87531	28.21
C.plumbea	1	0.00	87532	28.21
C.plumbeus	406	0.13	87938	28.34
C.punctatu	9	0.00	87947	28.34
C.reticula	25	0.01	87972	28.35
C.saxatili	15	0.00	87987	28.35
C.schizodo	1	0.00	87988	28.35
C.signatus	88	0.03	88076	28.38
C.spilurus	1147	0.37	89223	28.75
C.strigata	58	0.02	89281	28.77
C.tocantin	64	0.02	89345	28.79
C.tucurui	60	0.02	89405	28.81
C.xinguens	25	0.01	89430	28.82
Centromoch	12	0.00	89442	28.82
Cetopsis	1	0.00	89443	28.82
Characidiu	608	0.20	90051	29.02
CorydorasA	1	0.00	90052	29.02
CorydorasB	15	0.00	90067	29.02
Crenicich7	2	0.00	90069	29.03
Curimata	2128	0.69	92197	29.71
Curimatida	6	0.00	92203	29.71
E.electric	17	0.01	92220	29.72
E.macrops	723	0.23	92943	29.95
E.paradoxu	674	0.22	93617	30.17
E.trilinea	267	0.09	93884	30.25
Eigenmann1	11	0.00	93895	30.26
F.amazona	2	0.00	93897	30.26
G.carapo	44	0.01	93941	30.27
G.gulo	1423	0.46	95364	30.73
G.joselima	1210	0.39	96574	31.12
GlanidiumA	73	0.02	96647	31.14
GlanidiumB	10	0.00	96657	31.15
Gymnorham1	102	0.03	96759	31.18
H.acipense	482	0.16	97241	31.34
H.armatus	4457	1.44	101698	32.77
H.durivent	4	0.00	101702	32.77
H.efasciat	4	0.00	101706	32.78
H.ericae	219	0.07	101925	32.85
H.lacerdae	43	0.01	101968	32.86
H.littoral	191	0.06	102159	32.92
H.malabari	1229	0.40	103388	33.32
H.marginat	303	0.10	103691	33.41
H.mentalis	184	0.06	103875	33.47
H.microlep	12939	4.17	116814	37.64
H.platyrhy	540	0.17	117354	37.82
H.punctata	1	0.00	117355	37.82
H.spilomma	63	0.02	117418	37.84
H.spinosis	3	0.00	117421	37.84
H.tatauaia	54	0.02	117475	37.86
H.ternetzi	168	0.05	117643	37.91
H.unimacul	12044	3.88	129687	41.79
H.unitaeni	13	0.00	129700	41.80
H.wilderi	2703	0.87	132403	42.67
HomodiaetA	5	0.00	132408	42.67
HomodiaetB	1	0.00	132409	42.67
Hyphessobr	32	0.01	132441	42.68
Hypoptopom	553	0.18	132994	42.86
Hypostom10	1	0.00	132995	42.86
Hypostom11	9	0.00	133004	42.86
Hypostom12	1	0.00	133005	42.86
Hypostomu1	247	0.08	133252	42.94
Hypostomu2	25	0.01	133277	42.95
Hypostomu5	1255	0.40	134532	43.35
Hypostomu6	5	0.00	134537	43.35
Hypostomu7	6592	2.12	141129	45.48
Hypostomu8	31	0.01	141160	45.49
Hypostomu9	688	0.22	141848	45.71
Iguanodect	14	0.00	141862	45.72
J.apenima	685	0.22	142547	45.94
J.elassona	594	0.19	143141	46.13
J.polylepi	1067	0.34	144208	46.47
Jupiaba	16	0.01	144224	46.48
Knodus	52	0.02	144276	46.49
L.acipense	5	0.00	144281	46.50
L.affinis	1272	0.41	145553	46.90
L.batesii	19173	6.18	164726	53.08
L.bistriat	15	0.00	164741	53.09
L.desmotes	578	0.19	165319	53.27
L.fernande	132	0.04	165451	53.32
L.filament	4	0.00	165455	53.32
L.frideric	1861	0.60	167316	53.92
L.galaxias	301	0.10	167617	54.02
L.granti	1	0.00	167618	54.02
L.griseus	396	0.13	168014	54.14
L.maculatu	1	0.00	168015	54.14
L.octomacu	43	0.01	168058	54.16
L.pachyche	135	0.04	168193	54.20
L.praelong	14	0.00	168207	54.21
L.taeniofa	1	0.00	168208	54.21
L.tigrinus	1521	0.49	169729	54.70
L.trifasci	15	0.00	169744	54.70
L.vittatus	84	0.03	169828	54.73
Leporinu1A	370	0.12	170198	54.85
Leporinu1B	441	0.14	170639	54.99
Leporinus2	257	0.08	170896	55.07
Leporinus3	340	0.11	171236	55.18
Leporinus6	6	0.00	171242	55.18
Leporinus8	3	0.00	171245	55.18
Leptobryco	15	0.00	171260	55.19
Loricaria	1083	0.35	172343	55.54
Loricariic	996	0.32	173339	55.86
M.dichrour	14025	4.52	187364	60.38
M.dispilom	26	0.01	187390	60.39
M.durivent	56	0.02	187446	60.41
M.hypsauch	76	0.02	187522	60.43
M.hysteros	541	0.17	188063	60.60
M.loweae	13489	4.35	201552	64.95
M.paucisqu	13	0.00	201565	64.95
M.platycep	127	0.04	201692	65.00
M.pyrophth	85	0.03	201777	65.02
M.setiger	1251	0.40	203028	65.43
M.tergimac	536	0.17	203564	65.60
M.thoracat	1	0.00	203565	65.60
M.torquatu	525	0.17	204090	65.77
M.uranosco	17	0.01	204107	65.77
Mastiglani	2	0.00	204109	65.77
MetynnisA	24	0.01	204133	65.78
MetynnisB	109	0.04	204242	65.82
MicroglanA	2	0.00	204244	65.82
MicroglanB	2	0.00	204246	65.82
Moenkhausi	4	0.00	204250	65.82
MyleusA	115	0.04	204365	65.86
MyleusB	173	0.06	204538	65.91
MyleusC	9	0.00	204547	65.92
MyleusD	13	0.00	204560	65.92
MyleusE	5	0.00	204565	65.92
MyloplusA	1	0.00	204566	65.92
MyloplusB	14	0.00	204580	65.93
N.leporhin	272	0.09	204852	66.01
O.hoppei	59	0.02	204911	66.03
O.niger	6951	2.24	211862	68.27
Otocinclus	240	0.08	212102	68.35
P.aiereba	44	0.01	212146	68.36
P.amazonic	10103	3.26	222249	71.62
P.araguaie	1758	0.57	224007	72.19
P.blochii	6504	2.10	230511	74.28
P.brachypo	115	0.04	230626	74.32
P.brevis	117	0.04	230743	74.36
P.calhamaz	7	0.00	230750	74.36
P.cayana	1868	0.60	232618	74.96
P.compress	646	0.21	233264	75.17
P.costatus	238	0.08	233502	75.25
P.cristata	403	0.13	233905	75.38
P.fasciatu	253	0.08	234158	75.46
P.flavipin	1054	0.34	235212	75.80
P.fourcroi	487	0.16	235699	75.95
P.granulos	1677	0.54	237376	76.50
P.grunnien	1156	0.37	238532	76.87
P.guianens	3	0.00	238535	76.87
P.halisodo	1	0.00	238536	76.87
P.hemiolio	23	0.01	238559	76.88
P.junki	1963	0.63	240522	77.51
P.mesopota	9	0.00	240531	77.51
P.microps	3534	1.14	244065	78.65
P.natterer	2183	0.70	246248	79.35
P.nemurus	24	0.01	246272	79.36
P.nigrican	3143	1.01	249415	80.37
P.nigrolin	1163	0.37	250578	80.75
P.ornatus	24	0.01	250602	80.76
P.pariolis	235	0.08	250837	80.83
P.pauciras	217	0.07	251054	80.90
P.pirinamp	1458	0.47	252512	81.37
P.serratus	63	0.02	252575	81.39
P.squamosi	8315	2.68	260890	84.07
P.tetramer	119	0.04	261009	84.11
P.vittata	60	0.02	261069	84.13
Pachyurus	194	0.06	261263	84.19
Paralorica	66	0.02	261329	84.21
Pe.flavipi	436	0.14	261765	84.35
Phenacorha	40	0.01	261805	84.37
Pimelodel1	97	0.03	261902	84.40
Pimelodel3	1	0.00	261903	84.40
PimelodusB	18	0.01	261921	84.40
PimelodusN	55	0.02	261976	84.42
Po.orbigny	1	0.00	261977	84.42
Porotergu1	2	0.00	261979	84.42
Porotergu2	3	0.00	261982	84.42
PotamotryA	20	0.01	262002	84.43
PotamotryB	19	0.01	262021	84.44
PotamotryC	59	0.02	262080	84.46
PotamotryD	1	0.00	262081	84.46
PotamotryE	27	0.01	262108	84.47
PotamotryF	7	0.00	262115	84.47
PotamotryG	40	0.01	262155	84.48
Potamotryg	77	0.02	262232	84.51
Pseudacan2	11	0.00	262243	84.51
R.affinis	4093	1.32	266336	85.83
R.boehlkei	45	0.01	266381	85.84
R.eastward	100	0.03	266481	85.87
R.geryi	335	0.11	266816	85.98
R.itacaiun	1	0.00	266817	85.98
R.lanceola	7	0.00	266824	85.98
R.lapidife	1421	0.46	268245	86.44
R.marmorat	109	0.04	268354	86.48
R.rostratu	52	0.02	268406	86.49
R.vulpinus	10991	3.54	279397	90.04
R.zygonect	8	0.00	279405	90.04
Retroculus	253	0.08	279658	90.12
RhamdiaB	13	0.00	279671	90.12
Rhamphispn	1	0.00	279672	90.13
Rivulus	11	0.00	279683	90.13
S.amazonic	238	0.08	279921	90.21
S.bondi	90	0.03	280011	90.23
S.brama	883	0.28	280894	90.52
S.eigenman	1550	0.50	282444	91.02
S.gracilis	328	0.11	282772	91.12
S.hilarii	121	0.04	282893	91.16
S.jurupari	1383	0.45	284276	91.61
S.lima	650	0.21	284926	91.82
S.macrurus	54	0.02	284980	91.84
S.maculatu	150	0.05	285130	91.88
S.marmorat	9	0.00	285139	91.89
S.muelleri	3	0.00	285142	91.89
S.planicep	13	0.00	285155	91.89
S.rhombeus	7641	2.46	292796	94.35
S.rostratu	398	0.13	293194	94.48
S.tucuruie	1	0.00	293195	94.48
S.vittatus	1006	0.32	294201	94.81
Schultzich	17	0.01	294218	94.81
Serrasalm1	57	0.02	294275	94.83
St.nattere	7	0.00	294282	94.83
Sternarch2	1	0.00	294283	94.83
Sternarcho	1	0.00	294284	94.83
T.albus	5904	1.90	300188	96.74
T.argenteu	637	0.21	300825	96.94
T.auritus	110	0.04	300935	96.98
T.chalceus	1750	0.56	302685	97.54
T.galeatus	276	0.09	302961	97.63
T.piresi	239	0.08	303200	97.71
T.stellatu	154	0.05	303354	97.76
T.trifurca	2487	0.80	305841	98.56
Tatia1	67	0.02	305908	98.58
Tatia2	65	0.02	305973	98.60
Tatia3	152	0.05	306125	98.65
Tatia4	1	0.00	306126	98.65
TetragonoA	681	0.22	306807	98.87
TetragonoB	3	0.00	306810	98.87
Tometes	65	0.02	306875	98.89
V.cirrhosa	170	0.05	307045	98.95
VandelliaA	22	0.01	307067	98.95
VandelliaC	22	0.01	307089	98.96
Z.zungaro	269	0.09	307358	99.05
camarao	61	0.02	307419	99.07
caranguejo	2	0.00	307421	99.07
descarte	955	0.31	308376	99.38
hibrido	27	0.01	308403	99.38
jovem	9	0.00	308412	99.39
juvenil	1892	0.61	310304	100.00
larva	11	0.00	310315	100.00

Referência:
Verifique item 4 http://mduft.wikidot.com/aula3