Mastering Python Lists. Essential Skills For Every Programmer

102 Pages·5.65 MB·English

by  Poulin M.

Mastering Python Lists
MarPco ulin
Janu2a0r2,y0 16
Contents
BeyoCnRdU D 7
1 Hello World! 9
HelWloor ld! 10
TraiCloimnmga s 10
2 EmptLyi sts 13
The O[p e]r a.t o.r . . . . . . . . . . . 14
TheL isFtu(n)c t.i.o.n. ...... . 14
CreatAi Lnigt eLriaslt Of Empty Lists 16
CreatAi nLgi st Of WEimtphA t yL CiLosimtsp htresen sion 16
AvoiUds iTnhgeR epeOapte ra.t.o.r. ......... .. 18
3 ConverTtoi ngO tThyepre s 21
ConverAt LiinsTgto SAe .t . . 22
ConverAt LiinsTgto DAi cti.o nary 22
ConverAt SitnrgTi on g A List 22
Converat ilnigss te. t t o a 23
4 UnpackaiL nigs t 25
UnpacIkniP nygt h3o.nX. ........ . 28
UnpacAk iLnigsI tn tFou nctAirognu ments 30
5 IteraOtvienargL ist 33
IterOabbjleec. t .s .. 34
IteraOtvieAnrlg Il t ems 36
TheF oSrt ate.m e.n t. 36
TheE numerFautnec tion 36
6 Copyian gL ist 39
LisVta ria.b.l es 40
TheL isFtu(n)c tion 40
3
4 CONTENTS
The CoFpuyn(c.)t ion 40
Sli.c.i.n.g. .... 40
Lisats sig.n ment 41
Copywiintgth hl ei sfutn(c)t. i on 41
7 Subscripts 43
ReadAinndgW ritLiinsIgtt ems 44
Lisitn dexes 45
8 Ranges 47
Parameters 48
Examples . 48
9 Range Slices 49
Default Values 50
ForwRaarndgS el ices 50
With PoPsairtaimveet ers 50
WitNhe gatPiavrea m.e ters 51
ReveRrasnegS el ices . . . . . . . 52
With PoPsairtaimve.et ers 52
WitNhe gatPiavrea m.e ters 53
Summary 55
10 LSilsitc es 57
SliScyen .t ax 58
Quick Copy . 58
QuiRcekv erCsoepdy 58
Cop.y. ... 59
Revecrospey . 59
ForwLairsSdtl ices . 61
Default Values 61
SkippIitne.gm s. 64
ReveLrisset Slices 64
Default. .V alues 64
11 List Comprehensions 67
Examp.l.e. .1. ... 68
Examp.l.e. .2. ... 68
DiffereBnectewsPe yent h2o.nAx n d3 .x 69
CONTENTS 5
12B ooleOapne rations 71
EqualaniIdtd ye nt.i t.y . . . 72
Iafn Wdh ile Statements . . . . 72
The AannyAd( l)l () Functions 73
13P rocesMsuilntgi Lpilset s 75
ProceLsissiItnnsg Series 76
TheZ ipF(u)n ct.i.on 76
Unzip.pi.ng. .. . . 77
TranspoAs Miantgr ix 77
TciT aTco e. . .. . . 79
14S orting 81
SortIinPn lga ce 82
CreatAi Snogr tCeodp y 82
ReveSrosre.t . . . . 82
SpeciAf SyoirKnteg y 82
LambFduan ct.i on.s 83
15A ddinIgt emTso LAi st 85
AddiOnngeI teTmo The End 86
ExtenAd Liinsg.t . . . . . . . 86
AddiOnngeI teImn TMhied dle 87
AddiMnulgt iIptleeIm ns TMhied dle 88
16R emoviIntge mFrso ma List
89
RemovinIgt eBAmyn Index . .
90
RemovOinneOg r M orIet eBmysV alue
90
17R eversai nLgi st 91
ReverFsuendc tion 92
18R emoviDnugp licVaatleu es
93
RemovDiunpgl iWciatthueotPs r eseOrrvdienrg
94
RemovDiunpgl iWchaitPlerese seOrrvdienrg
94
19S earchfoirVn agl ues 95
TestFionTrgh eP reseOnfAc neI tem 96
FindTihneIg n dOefxA nI te.m . . . 96
FindTihneIg n deOxfeD su plic.a t.e s 96
FindTihneLg a rgOers tS maVlalleuset 96
FindTihnIeg n dOefxT heL argOers tS maVlalleuset 97
6 CONTENTS
20C ounting 99
The Count() Method . 100
TheC ounCtlears s . . 100
Introduction
Lisatrsaep owerfefualt uorfPe y thbounmt o sbto ooknsl syc ratthcsehu rface.
Thetye aycohtu h bea ssiycn t(atxh" ew habtu"lt)e aovuept r acteixcaamlp les
(th"ew hyT"h)i.bs o ogko ebse yobnadss iycn taanxtd r iteos shotwh reye oaul
powoefrl ists.
So wahrye lni'smtto srw ei deulsye d?
Wheyno fiur slte atropn r ogrtahmfe,o ciusos n l eartnoiw nogrw ki th indi­
vidvuaarli aabnlodeb sj eLcitsst.s reqguoib reey otnyhdoaw uta yot fto h inking
ansde yeo udra tian" chuniknss"t ead.
Manpyr oblaermbese ssto lvbeymd a nipullaitsoitfdns ag t Pay.t holni'sst
operaatraoen r ast ufirtfa oltr h etsyep oefps r oblTehmesly.ey to u wsroiltuet ions
thaatrb eo tcho mpaacnetdffi cieInnst h.o brytl ,e artnoi n"gt hliinskyt osui" n
wiblelc ombee taPt yetrh porno grammer.
Beyond CRUD
Iyfo u'wvoer ked with dmaitgabhbetfa asmeiswl,ii ttahyhra oe cu r onCyRmU D
C c-reate
R - read
U - update
D d-elete
Theasreae l tshofe o ubra sliicos pte ratYioouhn asvt.eo abbelt eoc reaal ties t,
reavda lfruoemst hlei msotd,i tfhlyei scto'nst eanntddse ,li etteefrm osmt hlei st.
BuPty thobnu'iisln t funclteyitoo un msdu ocm ho rBey.t he time you finish this
booyko wui blela l iesxtp ert.
7
8 CONTENTS
Chapter 1
HelWloor ld!
9
10 CHAPTER 1. WHOERLLLDO!
Hello World!
Itc'uss totmosa trayarp tr ogrambmoiownkig ta sh i mp"lHeeW lolrol edx!a"m ple,
anwdh oa m I tow ibttrhre aadki tion?
greeting = [''HWeolrllod'',]
Thiiss " lai tdeerfianli"ot fai l oinsI tt. coonfas c iosmtmsa -sespearroaifte esd
valeunecsl osseqdu abrirena ckTehtipssa. r tilciucslotan rt tawisont sr vianlgu es.
Lisctascn o ntaanityny poefv alaunedd,i ffetryepncetas bn e m ixteodg eitnh er
thsea mlei sLti.vs atl cuaesnsp amnu ltliipnlHeees r.e siasm leti fhsoetr matted
a bdiitff er.e ntly
greeting = [
'Hello',
'World'
J
Trailing Commas
Thel aistt em inc abnae f loilsltbo yw eodap nt i"otnraali cloimnmga ". This
commhaa nso e ffecbtuP,ty thon alylooduwo sn h'iattv ets rote ota htle a st
valduieff erfreonmtt lhoyet hers.
greeting = [
'Hello',
'World', # trailingc omma
J