Python快速入门by Armand文档格式.docx
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Python快速入门by Armand文档格式.docx
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hello."
+name+"
!
#hereisexplanatorynote
doublequotationmarksisequaltosingleoneinstringusage.
exp:
let'
sgo"
print'
let\'
sto'
\"
hello,world\"
shesaid"
stringsmerge:
sknow"
aboutyou"
or
x="
hello"
y="
everyone"
x+y
>
helloworld"
'
helloworld'
10000L
helloworld
print10000L
10000
Butsometimesweneedtoknowthedetailsofthevalueprinted.
printrepr("
printrepr(10000L)
printstr("
hello,world"
hello,world
printstr(10000L)
functioninputandraw_input:
name=input("
plsinputyourname:
)--youneedtoinput"
wangwei"
)--youneedtoinputwangwei
2datastructureinPython
Mostimportantdatastructureofpythonissequencewhichincludelist
(1)tuple
(2)string(3)andsoon.
listcanbemodifiedandtuplecan'
tbemodified.listcanreplacetupleinalmostalltheconditionexceptbeingthekeyofdictionary.
theindexofsequencewillstartfrom0.
Asequencecanbeincludedinanotherone.as:
wang=["
23]
zhang=["
zhangsheng"
25]
database=[wang,zhang]
database
Generaloprationsofsequence
1indexing
greeting='
hello'
greeting[0]
greeting[-1]
#willbeo
ifafunctionreturnasequence,wecanputindexingoperationonitdirectly.
fourth=raw_input(year:
)[3]
year:
2005
fourth
5'
2sliceing--accesstoarangeofelements
tag[left,right]
leftisthebeginningindex.
rightistheindexafterthelastelement.
numbers=[1,2,3,4,5,6,7,8,9.10]
numbers[3:
6]
[4,5,6]
numbers[0:
1]
[1]
numbers[-3:
-1]
[8,9]
]
[8,9,10]
numbers[:
3]
[1,2,3]
willprintallmembers
3adding---meansmerging
[1,2,3]+[4,5,6]
[1,2,3,4,5,6]
+'
world'
4multiply--meansrepeat
python'
*5
pythonpythonpyhonpythonpython'
[42]*2
[42,42]
5checking
permissions='
rw'
w'
inpermissions
True
6internalfunctionsasmin(),max(),len()isuseful
3List-slaveofpython
Listismutable.
list('
['
h'
'
e'
l'
********************Basicoperationoflist******************************
allbasicoperationsofsequencecanbeappliedtolist.
1modifythemember
x=[1,1,1]
x[1]=2
x
[1,2,1]
2deletethemember
names=['
wangwei'
zhangsheng'
bill'
delnames[2]
names
3shardingassignmeng
name=list('
perl'
name[1:
]=list('
ython'
name
p'
y'
t'
o'
n'
numbers=[1,5]
numbers[1:
1]=[2,3,4]
numbers
[1,2,3,4,5]
********************methodoflist***************************************
1append--addingoneobjecttotheendofthelist
lst=[1,2,3]
lst.append(4)
lst
[1,2,3,4]
2x.count(member)
3extend---addinganewlisttotheendofthelist
a=[1,2,3]
b=[4,5,6]
a.extend(b)
a
itisfundamentallydiffrentfrom'
extendmethodmodifytheoriginlist,'
returnanewlist.
4returnthematchingmember'
sposition
wang=['
wang'
wei'
shi'
wang.index('
5insert--insertnewobjecttothelist
numbers=[1,2,3,5,6,7]
numbers.insert(3,'
four'
[1,2,3,'
5,6,7]
6pop--delamemberandreturnit.
x=[1,2,3]
x.pop()---poplastmemberdefaultly
3
7remove--delfirstmatchingmember
x=['
x.remove('
8reverse--reversethelist,modifybutdonotreturnthenewlist
9sort
x=[1,4,2,3,5]
x.sort()
sorted
y=sorted(x)
[1,4,2,3,5]
y
4TupleString-unmutable
*****************************tuple***************************************
1,2,3
(1,2,3)
(42,)
tuple([1,2,3])
tuple('
abc'
('
a'
b'
c'
tupleisnotcomplicated.Creatandaccessit.
*****************************string**************************************
allbasicoperationsofsequencecanbeappliedtostring.
formatstring
onlytupleanddictionarycanformatonemorevalues.
format="
hello%s.welcome%s"
values=('
here'
printformat%values
************************methodofstring***********************************************
1find--searchingsub-string.returnleftindexwhenfindit
2join--mergestringlistwithaspecificcharactor
dirs='
usr'
bin'
env'
/'
.join(dirs)
/usr/bin/env'
3lower--returnthelowercaseofthestring
4replace
thisisatest'
.replace('
is'
eez'
theezeezatest
5split--inversemethodofjoin
.split('
5Dictionary--whenindexisnotgood
whenaccessamemberbyname,weusedictionary.wecallthisdatastructuremapping.thevalueofdictionarydonothavespecialsequence,theyallstoreinaspecifickey.thekeycouldbenumber,string,eventuple.
***********************creatandaccess**********************************
phonebook={'
alice'
321'
123'
}
phonebook['
creatdictionaryby(key,value)orparaemeters--usefunctiondict()
item=[('
name'
),('
age'
18'
)]
d=dict(item)
d['
wangwei
d=dict(name='
age='
21'
d={}
]='
***********************basicoperation*********************************
theoperationissimilartosequence
1len(d)--returnthenumberof(key,value)
2d[k]--returnvalueonkeyk
3d[k]=v--assignment
4deld[k]--deletethespecificmember
5kind--checkspecificmember
123,'
456}
myphoneis%('
)s'
%phonebook
***********************methodofdictionary******************************
1clear--deleteallmemberofdictionary
y=x
x={}
{...}
x.clear()
{}
2copy--returnasamedictionary.(shallowcopy,isassociate)
y=x.copy()
deepcopy--deepcopyfunction(isnotassociate)
fromcopyimportdeepcopy
y=x.deepcopy(x)
3fromkeys--creatanewdictionarybyseveralkeys.thevalueisnone
{}.fromkeys(['
])
4get--amorecomfortablewaytoaccessdictionary
d.get('
N/A'
)--whenaceessfailed,returnN/Anotnone
6Conditioncycleandotherstatement
*************************morefeature************************************
usepirntx,y,ctopirntmorethanoneexpression
frommathimportsqrtasfoobar
foobar(4)
2.0
morethanoneassignmentoperationcanberunningatthesametime.
x,y,z=1,2,3
x,y=y,x
values
(1,2,4)
x,y,z=values
chainassignment:
x=y=z
augmentedassignment:
x=2
x+=1
x*=2
fnord='
foo'
fnord+='
bar'
fnord*=2
fnord
foobarfoobar'
statementblock
runorrunseveraltimewhenconditionistrue.Creatblockbysettingspacebeforestatement.
FalseNone0"
()[]{}willberecognizedasFalse
True==1
False==0
False
*****************************if****************************************
ifname.endswith('
):
print'
elifname.endswith('
print'
welcome'
else:
thenumberis0'
****************************comparisonoperator**************************
x==y
x<
x>
=y
x!
xisy
xisnoty
xiny
xnotiny
***************************booleanoperator******************************
ifnumber<
=10andnumber>
=1:
great!
wrong!
***************************assert****************************************
ifnotcondition
crashprogram
wecanuseassertinsteadofit.
age=10
asert0<
age<
100
age=-1
assert0<
***************************while*****************************************
x=1
whilex<
=100
printx
x+=1
***************************for******************************************************
everymembercanrunthestatementblockonetime
num=[1,2,4,5,7,8]
fornumberinnum:
printnumber
1
2
4
5
7
8
gothroughallthememberofdictionary
d={'
x'
1,'
2,'
z'
3}
forkeyind:
printkey,'
correspondsto'
d[key]
**************************jumpoutofloop*******************************
forninrange(99,0,-1):
root=sqrt(n)
ifroot==int(root):
printn
break
*************
forxinseq:
ifcondition1:
continue
dosomething()
whileword:
word=raw_input('
plsenter:
whiletrue
word=raw_input('
ifnotword:
break
elsestatementwillrun,onlywhenbreakdoesn'
trun
frommathimp
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