DataFrame-数据检查

23 minute read

Published:

导入pandas库,为了方便起见也导入numpy库

import pandas as pd
import numpy as np

导入数据源

df = pd.read_csv("pokemon_data.csv",encoding="gbk")
df
姓名类型1类型2总计生命值攻击力防御力速度时代
0BulbasaurGrassPoison318454949451
1IvysaurGrassPoison405606263601
2VenusaurGrassPoison525808283801
3VenusaurMega VenusaurGrassPoison62580100123801
4CharmanderFireNaN309395243651
5CharmeleonFireNaN405586458801
6CharizardFireFlying5347884781001
7CharizardMega Charizard XFireDragon634781301111001
8CharizardMega Charizard YFireFlying63478104781001
9SquirtleWaterNaN314444865431
10WartortleWaterNaN405596380581
11BlastoiseWaterNaN5307983100781
12BlastoiseMega BlastoiseWaterNaN63079103120781
13CaterpieBugNaN195453035451
14MetapodBugNaN205502055301
15ButterfreeBugFlying395604550701
16WeedleBugPoison195403530501
17KakunaBugPoison205452550351
18BeedrillBugPoison395659040751
19BeedrillMega BeedrillBugPoison49565150401451
20PidgeyNormalFlying251404540561
21PidgeottoNormalFlying349636055711
22PidgeotNormalFlying4798380751011
23PidgeotMega PidgeotNormalFlying5798380801211
24RattataNormalNaN253305635721
25RaticateNormalNaN413558160971
26SpearowNormalFlying262406030701
27FearowNormalFlying4426590651001
28EkansPoisonNaN288356044551
29ArbokPoisonNaN438608569801
..............................
770SylveonFairyNaN525956565606
771HawluchaFightingFlying5007892751186
772DedenneElectricFairy4316758571016
773CarbinkRockFairy5005050150506
774GoomyDragonNaN300455035406
775SliggooDragonNaN452687553606
776GoodraDragonNaN6009010070806
777KlefkiSteelFairy470578091756
778PhantumpGhostGrass309437048386
779TrevenantGhostGrass4748511076566
780PumpkabooAverage SizeGhostGrass335496670516
781PumpkabooSmall SizeGhostGrass335446670566
782PumpkabooLarge SizeGhostGrass335546670466
783PumpkabooSuper SizeGhostGrass335596670416
784GourgeistAverage SizeGhostGrass4946590122846
785GourgeistSmall SizeGhostGrass4945585122996
786GourgeistLarge SizeGhostGrass4947595122696
787GourgeistSuper SizeGhostGrass49485100122546
788BergmiteIceNaN304556985286
789AvaluggIceNaN51495117184286
790NoibatFlyingDragon245403035556
791NoivernFlyingDragon5358570801236
792XerneasFairyNaN68012613195996
793YveltalDarkFlying68012613195996
794Zygarde50% FormeDragonGround600108100121956
795DiancieRockFairy60050100150506
796DiancieMega DiancieRockFairy700501601101106
797HoopaHoopa ConfinedPsychicGhost6008011060706
798HoopaHoopa UnboundPsychicDark6808016060806
799VolcanionFireWater60080110120706

800 rows × 9 columns

1.查看前5行和后5行

head()默认返回前面5行

df.head()
姓名类型1类型2总计生命值攻击力防御力速度时代
0BulbasaurGrassPoison318454949451
1IvysaurGrassPoison405606263601
2VenusaurGrassPoison525808283801
3VenusaurMega VenusaurGrassPoison62580100123801
4CharmanderFireNaN309395243651

从头开始指定查看行数

df.head(20)
姓名类型1类型2总计生命值攻击力防御力速度时代
0BulbasaurGrassPoison318454949451
1IvysaurGrassPoison405606263601
2VenusaurGrassPoison525808283801
3VenusaurMega VenusaurGrassPoison62580100123801
4CharmanderFireNaN309395243651
5CharmeleonFireNaN405586458801
6CharizardFireFlying5347884781001
7CharizardMega Charizard XFireDragon634781301111001
8CharizardMega Charizard YFireFlying63478104781001
9SquirtleWaterNaN314444865431
10WartortleWaterNaN405596380581
11BlastoiseWaterNaN5307983100781
12BlastoiseMega BlastoiseWaterNaN63079103120781
13CaterpieBugNaN195453035451
14MetapodBugNaN205502055301
15ButterfreeBugFlying395604550701
16WeedleBugPoison195403530501
17KakunaBugPoison205452550351
18BeedrillBugPoison395659040751
19BeedrillMega BeedrillBugPoison49565150401451

tail()默认返回后面5行

df.tail()
姓名类型1类型2总计生命值攻击力防御力速度时代
795DiancieRockFairy60050100150506
796DiancieMega DiancieRockFairy700501601101106
797HoopaHoopa ConfinedPsychicGhost6008011060706
798HoopaHoopa UnboundPsychicDark6808016060806
799VolcanionFireWater60080110120706

从尾查看指定查看行数

df.tail(20)
姓名类型1类型2总计生命值攻击力防御力速度时代
780PumpkabooAverage SizeGhostGrass335496670516
781PumpkabooSmall SizeGhostGrass335446670566
782PumpkabooLarge SizeGhostGrass335546670466
783PumpkabooSuper SizeGhostGrass335596670416
784GourgeistAverage SizeGhostGrass4946590122846
785GourgeistSmall SizeGhostGrass4945585122996
786GourgeistLarge SizeGhostGrass4947595122696
787GourgeistSuper SizeGhostGrass49485100122546
788BergmiteIceNaN304556985286
789AvaluggIceNaN51495117184286
790NoibatFlyingDragon245403035556
791NoivernFlyingDragon5358570801236
792XerneasFairyNaN68012613195996
793YveltalDarkFlying68012613195996
794Zygarde50% FormeDragonGround600108100121956
795DiancieRockFairy60050100150506
796DiancieMega DiancieRockFairy700501601101106
797HoopaHoopa ConfinedPsychicGhost6008011060706
798HoopaHoopa UnboundPsychicDark6808016060806
799VolcanionFireWater60080110120706

2.查看列名

df.columns
Index(['姓名', '类型1', '类型2', '总计', '生命值', '攻击力', '防御力', '速度', '时代'], dtype='object')
for i in df.columns:
    print(i)
姓名
类型1
类型2
总计
生命值
攻击力
防御力
速度
时代

3.查看索引

df.index
RangeIndex(start=0, stop=800, step=1)
[print(i) for i in df.index]
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4.查看行列数

df.shape
(800, 9)

5.查看数据类型

查看所有列的数据类型

df.dtypes
姓名     object
类型1    object
类型2    object
总计      int64
生命值     int64
攻击力     int64
防御力     int64
速度      int64
时代      int64
dtype: object

查看某列的数据类型

df["攻击力"].dtypes
dtype('int64')

6.查看空值

df.isnull().head()
姓名类型1类型2总计生命值攻击力防御力速度时代
0FalseFalseFalseFalseFalseFalseFalseFalseFalse
1FalseFalseFalseFalseFalseFalseFalseFalseFalse
2FalseFalseFalseFalseFalseFalseFalseFalseFalse
3FalseFalseFalseFalseFalseFalseFalseFalseFalse
4FalseFalseTrueFalseFalseFalseFalseFalseFalse
df[df["类型2"].isnull()]
姓名类型1类型2总计生命值攻击力防御力速度时代
4CharmanderFireNaN309395243651
5CharmeleonFireNaN405586458801
9SquirtleWaterNaN314444865431
10WartortleWaterNaN405596380581
11BlastoiseWaterNaN5307983100781
12BlastoiseMega BlastoiseWaterNaN63079103120781
13CaterpieBugNaN195453035451
14MetapodBugNaN205502055301
24RattataNormalNaN253305635721
25RaticateNormalNaN413558160971
28EkansPoisonNaN288356044551
29ArbokPoisonNaN438608569801
30PikachuElectricNaN320355540901
31RaichuElectricNaN4856090551101
32SandshrewGroundNaN300507585401
33SandslashGroundNaN45075100110651
34Nidoran♀PoisonNaN275554752411
35NidorinaPoisonNaN365706267561
37Nidoran♂PoisonNaN273465740501
38NidorinoPoisonNaN365617257651
40ClefairyFairyNaN323704548351
41ClefableFairyNaN483957073601
42VulpixFireNaN299384140651
43NinetalesFireNaN5057376751001
55DiglettGroundNaN265105525951
56DugtrioGroundNaN4053580501201
57MeowthNormalNaN290404535901
58PersianNormalNaN4406570601151
59PsyduckWaterNaN320505248551
60GolduckWaterNaN500808278851
..............................
721FennekinFireNaN307404540606
722BraixenFireNaN409595958736
724FroakieWaterNaN314415640716
725FrogadierWaterNaN405546352976
727BunnelbyNormalNaN237383638576
732ScatterbugBugNaN200383540356
733SpewpaBugNaN213452260296
737FlabébéFairyNaN303443839426
738FloetteFairyNaN371544547526
739FlorgesFairyNaN552786568756
740SkiddoGrassNaN350666548526
741GogoatGrassNaN53112310062686
742PanchamFightingNaN348678262436
744FurfrouNormalNaN4727580601026
745EspurrPsychicNaN355624854686
746MeowsticMalePsychicNaN4667448761046
747MeowsticFemalePsychicNaN4667448761046
752SpritzeeFairyNaN341785260236
753AromatisseFairyNaN4621017272296
754SwirlixFairyNaN341624866496
755SlurpuffFairyNaN480828086726
762ClauncherWaterNaN330505362446
763ClawitzerWaterNaN500717388596
770SylveonFairyNaN525956565606
774GoomyDragonNaN300455035406
775SliggooDragonNaN452687553606
776GoodraDragonNaN6009010070806
788BergmiteIceNaN304556985286
789AvaluggIceNaN51495117184286
792XerneasFairyNaN68012613195996

386 rows × 9 columns

7.查看数据表信息

df.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 800 entries, 0 to 799
Data columns (total 9 columns):
姓名     800 non-null object
类型1    800 non-null object
类型2    414 non-null object
总计     800 non-null int64
生命值    800 non-null int64
攻击力    800 non-null int64
防御力    800 non-null int64
速度     800 non-null int64
时代     800 non-null int64
dtypes: int64(6), object(3)
memory usage: 56.3+ KB

8.查看唯一值

df["类型1"].unique()
array(['Grass', 'Fire', 'Water', 'Bug', 'Normal', 'Poison', 'Electric',
       'Ground', 'Fairy', 'Fighting', 'Psychic', 'Rock', 'Ghost', 'Ice',
       'Dragon', 'Dark', 'Steel', 'Flying'], dtype=object)

所有唯一值的数量

len(df["类型1"].unique())
18

每个值出现的次数(频次)

df["类型1"].value_counts()
Water       112
Normal       98
Grass        70
Bug          69
Psychic      57
Fire         52
Rock         44
Electric     44
Ghost        32
Dragon       32
Ground       32
Dark         31
Poison       28
Fighting     27
Steel        27
Ice          24
Fairy        17
Flying        4
Name: 类型1, dtype: int64