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TableofContents
1.1Introduction1
1.2GettingSetup2
1.3YourfirstPHPwebpage3
1.4Workingwithtext4
1.5Talkingtotheuser5
1.6Comparison&Ifstatements6
1.7If&Else7
1.8Cleaningupthegame8
1.9Rememberingvalues9
1.10Finishingyourgame10
I'mlearning:PHP
BEGINNERPHP
1
IntroductionI'mlearning:PHP
BEGINNERPHP
2
TheseSushiCardswillhelpyoulearntobuildwebpagesusingPHP,averypopular
programminglanguagethat'susedtobuildwebsiteslikeFacebookandWikipedia.You
cancombineitwithHTML(andcheckouttheHTMLSushiCardsifyoudon'tknowhowto
codeHTMLyet!).
1
First,you'regoingtoneedsomewheretocode!PHPneedsafewdifferentpiecesinplace
tomakeitworkand,ifyou'regoingtoreleaseawebsitelater,you'lleventuallyneedto
learnhowtosetthatup.Fornow,though,let'sjustgetgoingquicklybyusingCloud9,an
onlineeditorthatwilldoallthesetupforyou!Checkitoutatdojo.soy/php-edit.
2
YoucanuseyourGitHuborBitbucketaccounttosigninifyouhaveone.Otherwise,sign
upwithyouremailaddress.3
Choose"Createanewworkspace"andfillitinasfollows:
Workspacename:beginner-php
Description:MyfirstPHPwebsite
MakesurethatHostedworkspaceisselected
ChooseaPrivateworkspace
SkipovertheClonefromGitorMercurialURL—youdon'tneedto
cloneanything
ChoosethePHP,Apachetemplate
4
GettingSetupI'mlearning:PHP
BEGINNERPHP
3
NowjustclickonCreateworkspaceandyou'reallset!5
Onceyourworkspaceisupandrunning,you'llnoticeyou'vebeengivenafewfiles,which
youcanseeinthesidebar.6
You'regoingtoneedtocreateanewfiletoputallyourcodein.Youcandothisby
choosingFile>NewFileinthemenu.7
Oncethefileisopened,youcansaveitbychoosingFile>SaveAsandgivingitaname.
Savethisonenowasindex.php8
You'rereadytomakeyourfirstPHPwebpage!9
GettingSetupI'mlearning:PHP
BEGINNERPHP
4
TimetostartcodingyourfirstrealPHPwebpage!You'regoingtostartwithoneofthe
classics,saying"Hello!"toyouruserand,bytheendofthesecards,you'llbemakinga
numberguessinggamefortheusertoplay!
1
So,tobeginwith,everyPHPwebpagewillhaveatleastalittlebitofHTMLinit.Startby
makingareallybasiconebytypingthiscodeintoyourindex.phpandsavingit.
<!DOCTYPEhtml>
<html>
<head>
<title>MyPHPwebpage</title>
</head>
<body>
ThisisjustHTMLtext,itisnotcleverlikeyourPHPtextwillbe!
</body>
</html>
Thethingsintheanglebrackets(<>)arecalledHTMLtagsandyou'llbecomingacross
afewoftheminthesecards.Therearelotsmore,though,andyoucanlearnaboutthem
intheHTMLSushiCardsandinloadsofotherplacesonline!
2
YourfirstPHPwebpageI'mlearning:PHP
BEGINNERPHP
5
Runthatpageandyou'llseeabasicHTMLpage.Tobeginwith,yourPHPpageisgoing
tolookprettysimilar,butveryquicklyyou'llbeusingthepowerofPHPtodothingsthat
HTMLnevercouldalone!Togetstarted,replacethatHTMLtextwithsomespecialPHP
code.
<body>
<?php
echo"Helloeveryone!ThisismyfirstPHPprogram!";
?>
</body>
NoticethatPHPcodealwaysappearsinside<?phpand?>.Thisissothecomputercan
tellwhichpartsarePHPandwhichpartsareHTML.Usingthese,youcanputPHPcode
anywhereinsidetheHTML.
Also,noticethatthePHPcodealwaysendseachlinewithasemicolon(;).Thisisso
PHPknowstoendthiscommandandstartanother.Ifyouforgettodothis,PHPcanget
veryconfused.
3
NowsaveandrunyourPHPfile.Congratulations!Ifitallworked,you'vejustwrittenyour
firstPHPwebpage!4
YourfirstPHPwebpageI'mlearning:PHP
BEGINNERPHP
6
Nowit'stimetostartworkingonyourgame!Thefirstthingyou'regoingtoneedistoteach
theplayertherules.
Youmightwanttochangethingslikethesmallestandbiggestnumbers,orthenumberof
guessesyou'regoingtogivetheplayer.IfyouwroteouttheruleswithplainHTML,you'd
havetogobackandre-writethemeverytimeyouchangedanyofthosethings.Youdon't
needtodothat,though.YoucanusePHPandvariablestoincludethenumbersaspart
ofyourtext!
1
First,you'regoingtoneedtotoupdateyourtext,sochangethePHPcodeonyourpage
tothis:
echo"I'vepickedanumberbetween1and9<br/>";
echo"Youwillhave5chancestotrytoguessmynumber!";
The<br/>isapieceofHTMLthattellsthebrowsertostartanewlineafterit.Youcan
putanyHTMLinsideyourPHPanditwillbetreatedexactlyasifithadbeenwrittenas
HTML.
Noticethatyou'reusingdoublequotes(")aroundyourtextinsteadofsinglequotes
('),fortworeasons:
PHPwillgetconfusedifyouuseanapostropheinsideofsinglequotes.
Tryitandsee!Whathappens,andwhy?
PHPwilldosomethingspecialinsideofdoublequotesthatitwon't
insideofsinglequotes,whichyou'llseebelow.
2
WorkingwithtextI'mlearning:PHP
BEGINNERPHP
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Nowit'stimeforyoutostartaddingvariables!Thesearelabelsthatyoucanusetostore
values,likeastringoftextoranumber.PHPremembersthosevaluesandletsyouuse
thevalueslaterbyusingtheirlabel.Thisletsyousetavalueonceanduseitloadsof
timesinyourprogram.
InPHP,allvariablenamesstartwithadollarsign($)andareusuallywrittenin
camelCase,wherethefirstwordstartswithasmall(lowercase)letter,thereareno
spaces,andanylaterwordsstartwithcapital(uppercase)letter.
Putthislinein,insidethe<?phpbutbeforetheecholines
$minValue=1;
$maxValue=9;
$guesses=5;
Allofthesevariablesarenumbers,butyou'llbeworkingwithtextvariableslater.
3
Now,updateyourtwoecholinessotheylooklikethis:
echo"I'vepickedanumberbetween{$minValue}and{$maxValue}<br/>";
echo"Youwillhave{$guesses}chancestotrytoguessmynumber!";
Noticethecurlybraces({and})aroundthevariablenamestotellPHPnottotreat
themlikeregulartext!
4
Runyourprogramandseewhathappens.Thentrychangingthevaluesofsomeofthe
variablesandrunitagain.Justmakesuretoseteverythingbacktothewayyou'vegotit
herebeforemovingon!
5
WorkingwithtextI'mlearning:PHP
BEGINNERPHP
8
Ok,soyoucangetinformationfromavariableandshowittotheplayerwithecho,but
howdoyougetinformationfromtheplayer?Afterall,thisisaguessinggame,soyou
needsomewaytocollecttheirguesses!
1
You'regoingtouseacombinationofHTMLandPHPtodothis.TheHTMLyou'llbeusing
isgoingtobenew,evenifyou'vealreadydonetheHTMLSushiCards,sincetheydon't
usemanyformsandyourPHPprogramswillprobablyusealotofthem.Youcansee
themonalmosteverywebsiteyouusetheinternetandthecodeforthemisprettyeasy!
<formmethod="get">
Yourguess:<inputtype="text"name="guess"/>
</form>
AHTMLformisasimpleidea:controls—liketextboxes,drop-downmenus,checkboxes
orbuttons—areusedtocollectinformationfromusersandsendthatinformationtoyour
PHPprogram.Sometimes,responsesaresenttotheusers.You'llbesendingresponses
inyourgames.
2
Now,timetoaddaformtoyourpage!SoyoucanusePHPvariablesandothercodein
creatingyourform,you'regoingtouseechostatementstocreateit,insteadofjusttyping
theHTMLintothefile.So,addthefollowingbelowyourtwoexistingechostatements:
echo"<formmethod="get">";
echo"Yourguess:<inputtype="text"name="guess"/>";
echo"</form>";
Runthiscodeandseewhathappens!
3
TalkingtotheuserI'mlearning:PHP
BEGINNERPHP
9
Well,thatdidn'tquiteworkright,didit?Anyideawhy?It'sbecauseofthedoublequotesin
<formmethod="get">.PHPisn'tsmartenoughtorecognisethattheyarepartoftheHTML
tag;itreadsthemastheendofthestringoftextthatechoistryingtoinsertintothe
page.Afterthat,it'slookingforasemicolon(;)butinsteaditfindsgandgetsvery
confused!Thiskindofproblemcancomeupquiteofteneitherbecauseyou'veforgotten
whichkindofquotestouseoryou'recopyingfromanotherofyourprogramsandused
quotesdifferentlythere.Luckily,it'sveryeasytofix.Justputabackslash(\)infrontof
yourallyourdoublequotes(don'tforgettheonesintheinputtag!)likethis,toescapethe
normalruleofendingthestring!
echo"<formmethod=\"get\">";
4
Runthecodeagain!Nowyou'vegotsomewhereforyourusertoputtheirtext!Type
somethinginandpresstheenterkey.WatchthepageURLinthebrowserandnotice
whatchanges!
5
TalkingtotheuserI'mlearning:PHP
BEGINNERPHP
10
ThetextthatappearedontheendoftheURLiscalledaqueryparameterandyoucan
haveloadsofthemonthesameURL.Theformautomaticallyaddedone(becauseyou
setmethod="get"),butyoucouldjustaseasilytypethemin,separatedbysemicolons.
PHPreadstheendoftheURLforthepageit'sloadedonandturnsallthequery
parametersintosomethingcalledakey,valuearray.Youdon'tneedtoknowexactly
whatthatisrightnow,we'llgointoitinalaterSushiCardseries.Whatyoudoneedto
knowishowtogetvaluesoutofit.
1
Allyouneedtodotogetavalueoutofthearrayispassinthekeyofavaluethat'sin
there.Sinceyourformaddstheguessfield,that'stheoneyou'llbelookingfor.You'll
wanttoassignthatvaluetoaplayerGuessvariable,soaddthislinejustbeforeallyour
echolines:
$playerGuess=$_GET['guess'];
2
Now,remindtheplayerwhattheirlastguesswasbyaddinganotherechojustbeforethe
inputform:
echo"Yourlastguesswas{$playerGuess}.<br/>";
Runthecode.Nowyou'retakinginputfromyourplayerandgivingitbacktothem.Very
cool!
3
Comparison&IfstatementsI'mlearning:PHP
BEGINNERPHP
11
TryremovingallthequeryparametersfromtheURLandreloadingthepage.Noticethat
younowget"Yourlastguesswas."
That'snotideal.Whatyouwanttohappenis:
Checkifthere'savalue(maybetheyhaven'tmadeaguessyet)
ifso,showthemessageaboutthelastguess
4
PHPcanfigureallthisoutanddoitforyou!Youjustneedtouseanifstatement.
Anifstatementusesatest(inbrackets),thathasananswerthat'seithertrueorfalse
and,ifit'strue,apieceofcodetorun.Youcandothistocheckifyourvariablecontains
anythinglikethis:
if(!empty($playerGuess)){
echo"Yourlastguesswas{$playerGuess}.";
}
Hereempty()isaspecialpieceofPHPthatcheckswhetherthevariableinsideits
bracketshasavalueandanswerseithertrueifitdoesn'torfalseifitdoes.The!before
itreversesthisanswer,turningatrueintoafalseandafalseintoatrue.Sowhatthis
codesaysis:"Ifthereisnotnovaluein$playerGuess,thenprintoutYourlastguesswas
[thevalueofplayerguess]."
Replaceecho"Yourlastguesswas{$playerGuess}.";withthecodeaboveandtestit
withandwithoutanswerstoseeitworking.
5
Comparison&IfstatementsI'mlearning:PHP
BEGINNERPHP
12
Nowthatyouknowhowtouseifstatements,youcanstartwritingthecodetogetyour
gametorun!You'lldealwithusingarandomnumberinalatercard,butfornowjustadd
anothervariableupatthetopwithalltheotherstosetyour"secret"number,likethis:
$secretNumber=5;
1
Whatyouwanttodonowiscomparetheplayer'sguesswiththesecretnumber,andtell
themiftheyguessedcorrectly.Tocompareonevaluetoanotherandgetatrueorfalse
result,youusetwoequalssigns(==).Ifthevaluesoneithersidearethesame,thenthe
resultistrue;otherwise,it'sfalse.
Here'showyou'dchecktheplayer'sanswerinyourPHP:
if($secretNumber==$playerGuess){
echo("<br/>That'sright!Iwasthinkingof{$secretNumber}!");
}
Addthiscodein(afterthosevariables'valuesareset!)andthenruntheprogram.Try
guessingcorrectly(i.e.5)andincorrectly.
2
If&ElseI'mlearning:PHP
BEGINNERPHP
13
Haveyounoticedafewissueswithwhat'shappeninghere?Foronething,theplayeris
stillaskedtopickanumberevenwhenthey'vewonthegame!Youcanfixthat,though,by
usingelsestatements,afteryourifstatements.Youcan'tuseelseonitsown,it
onlyrunsthecodeinsideitifthetestontheifstatementjustbeforeitwasfalse.
So,toonlyshowtheformforthenextguessiftheplayerhasnotyetguessedthesecret
number,youneedtoaddanelseontoyouriffromaboveandmovealltheformcode
intoit,likethis:
if($secretNumber==$playerGuess){
echo("<br/>That'sright!Iwasthinkingof{$secretNumber}!");
}
else{
echo"<formmethod='get'>";
echo"Yourguess:<inputtype='text'name='guess'/>";
echo"</form>";
}
3
If&ElseI'mlearning:PHP
BEGINNERPHP
14
Itdoesn'tmakesensetogivetheplayertheinstructionsonhowtoplayeverysingleturn.
However,itwouldbeusefultotellthemhowmanyguessestheyhaveleft.Todothis,
you'llneedtocreateanothervariable,guessesLeftandaddittoyourfile:
$guessesLeft=$guesses;
Notethatbecauseyouaresettingthisvariabletothevalueofanother,itmustbedeclared
afterthatvariable.
1
Next,taketherulesechocodeandstickitintoanifthatchecksifthenumberof
guessestheplayerhasleftisequaltothenumbertheystartedwith.Ifitis,thenyouknow
it'sthefirstturnandyoucanshowthemtherules.Ifit'snot,thentellthemhowmany
guessestheyhaveleft.
if($guessesLeft==$guesses){
echo"I'vepickedanumberbetween{$minValue}and{$maxValue}<br/>";
echo"Youwillhave{$guesses}chancestotrytoguessmynumber!<br/>";
}
else{
echo"Youhave{$guessesLeft}guessesleft.<br/>";
}
2
CleaningupthegameI'mlearning:PHP
BEGINNERPHP
15
Ifyourunthiscodeandplaythroughitafewtimes,you'llnoticethatthenumberof
guessesnevergoesdown!Therearetworeasonsofthat,andyou'llsolvethemoneata
time.ThefirstisthatyouneverdecreasethevalueofguessesLeft!Therearetwothings
youneedtodotomakethishappenandyou'llgothroughbothofthemonthiscard.First,
youneedtocheckiftheplayermadeaguessand,ifso,setguessesLefttoonelessthan
thecurrentvalue.
Youalreadyhavethetestformakingaguess,sinceyoucheckforaguessbefore
decidingwhethertoshow"Yourlastguesswas...".Youcanjustupdatethatcodeto
includeasecondlinethatdecreasesguessesLeft,likethis:
if(!empty($playerGuess)){
echo"Yourlastguesswas{$playerGuess}.";
$guessesLeft=$guessesLeft-1;
}
3
Nowit'simportanttokeepaneyeontheorderofyourcode.Ifyourunthiscodeas
written,you'llnoticethecountofguessesstilldoesn'tdrop!Thisisbecausetheecho
codethatprintsthevalueofguessesLeftrunsbeforethecodethatchangesthatvalue!All
youneedtodoismove(cutandpaste)thecodesoitcomesjustafterallyourvariable
declarationsatthestartandthingsshouldworkfine.Dothatnowandtryrunningitagain.
4
CleaningupthegameI'mlearning:PHP
BEGINNERPHP
16
You'llnoticethatnowthecountofguessesdoesgodownto4,butitnevergoesany
lower!Anyideawhy?It'sbecauseofthewayPHPworks:Everytimethepageloads,the
programrunsagainfromthestart,withnomemoryofthelasttimeitran!Thatmeansit
alwaysresetsthevalueofguessesLeftto5andthen,ifaguesswasmade,subtracts1.
So,whatyouneedtodohereisstorethatvaluesomewhereandpassitintotheprogram
thenexttimeitruns.Well,youalreadyhavesomethinglikethat:theformontheweb
page!YoucanwritethecurrentvalueofguessesLeftintotheformandreaditbackout
from$_GETlater.Startwiththewriting,byupdatingyourformcreationcodetolooklike
this:
echo"<formmethod='get'>";
echo"Yourguess:<inputtype='text'name='guess'/>";
echo"<inputtype='hidden'name='guessesLeft'value='{$guessesLeft}'/>";
echo"</form>";
Thetypeofthefieldis"hidden",soitwon'tbevisible,butwillbesentinontheURL.The
valueissettothecurrentvalueof'guessesLeft'.
1
RememberingvaluesI'mlearning:PHP
BEGINNERPHP
17
Nowyouneedtopickupthevalueyou'vesavedandwriteitintoguessesLeft.Thisgetsa
littlecomplicated,sincetherewon'talwaysbeavalueintheURL(thefirsttimethegame
isrun,forexample).Soyouneedtoreplacethecurrentline$guessesLeft=$guesseswith
this:
$guessesLeft=$_GET['guessesLeft'];
if(!isset($guessesLeft)){
$guessesLeft=$guesses;
}
ThiscodetriestogetthevaluefromtheURLand,ifitdoesn'tfindit,leavesguessesLeft
empty,whichcausesthecodeintheifstatementtorun,fillingitwiththevalueof
guesses.Thereasonwedidn'tuseemptyhereisbecauseemptywillgiveafalseifthe
valueis0,whichisgoingtohappenhere,whentheplayerrunsoutofguesses.Try
runningtheprogramagainandyou'llseethatitallworksnow!
2
Youmayhavenoticedonelastproblem:Thegamedoesn'tendwhenyourunoutof
guesses!We'lllookathowtofixthat,andhowtouseasecretnumberthatactually
changes,onthenextcard!
3
RememberingvaluesI'mlearning:PHP
BEGINNERPHP
18
First,let'slookatmakingtheplayerlosethegame.Thisneedstohappenwhenthey've
usedtheirlastguessup,sowhen$guessesLeft==0.Whenthishappens,keepshowing
themtheirlastguess,andthattheyhavenoguessesleft,butnottheformortherules.To
makethathappen,you'llneedtouseanewbitofcode:elseif.
1
Asyoumighthaveguessedelseifisacombinationoftheelseandifstatements.
Likeelse,itonlyhappensiftheconditioninanifstatementisfalse,butlikeifit
hasitsowncondition.
Youcanuseasmanyelseifstatementsasyouwant,butonlythefirstonethathasa
trueconditionwillrun.Ifnoneofthemaretrue,theelsestatementwillrun,justlikewith
aregularif.
Togetyourgametotelltheplayerthey'velost,youjustwanttoaddanelseiftothe
codethatcheckstheiranswerandshowsthemtheforto,iftheyhavenowguessesleft,
showthemadifferentmessageinstead,likethis:
if($secretNumber==$playerGuess){
echo("<br/>That'sright!Iwasthinkingof{$secretNumber}!");
}
elseif($guessesLeft==0){
echo("<br/>Gameover!Youlose!");
}
else{
echo"<formmethod='get'>";
echo"Yourguess:<inputtype='text'name='guess'/>";
echo"<inputtype='hidden'name='guessesLeft'value='{$guessesLeft}'/>";
echo"</form>";
}
2
FinishingyourgameI'mlearning:PHP
BEGINNERPHP
19
Ok,nowyouhaveagamewheretheplayercanguessanumber,getacertainnumberof
triesandbetoldiftheywinorlose.Verycool!However,rightnow,thatnumberisalways
5...whichislesscool.PHPisprettygoodatcomingupwithrandomnumbers,though.To
usearandomnumberinsteadyoujustneedtochangethecodeforsecretNumberlike
this:
$secretNumber=$_GET['secretNumber'];
if(!isset($secretNumber)){
$secretNumber=rand($minValue,$maxValue);
}
Therandisafunctionthattakestwonumbersandgivesyoubackarandomnumber
betweenthem.You'reusingminValueandmaxValueheresoyouonlyhavetochange
thosenumbersinoneplaceandthey'llchangeeverywhereinyourcode!
3
Nowyouneedtomakesurethatit'sthesamerandomnumberthroughoutthegame.It
wouldn'tbefairtokeepchangingitonyourplayer!Youalreadyknowhowtodothisone
though:ahiddenformfield.Justaddthistoyourechocodefortheguessingform(you
won'tneedtokeepstoringitiftheplayerwinsorloses!).
echo"<inputtype='hidden'name='secretNumber'value='{$secretNumber}'/>";
4
Now,trytoplayyourgame!5
Howelsecouldyouusethiscode?You'vegotallthepiecesheretomakeaquizoran
interactivestory,whereyoukeepscore,askdifferentquestionsoneachpageandeven
sendtheplayerindifferentdirectionsbasedontheiranswers!
6
FinishingyourgameI'mlearning:PHP
BEGINNERPHP
20
FinishingyourgameI'mlearning:PHP
BEGINNERPHP
21
