python入門基礎(chǔ)代碼

1、python 入門基礎(chǔ)代碼#查找 index 函數(shù)的幫助help(str.index) #for 循環(huán)和 break 語句from math import sqrt for i in range(2,101): flag=1 k=int(sqrt(i) for j in range(2,k 1): if i%j=0: flag=0 break if(flag): print i #continue 語句 ,滿足條件跳出 continue 后面的語句sumA=0 i=1 while i<=5: sumA =i i =1 if i=3:continue print 'i=%d,sum

2、=%d'%(i,sumA) #循環(huán)中的 else 語句k=5 for i in range(1,10): if k=3: break else: print i #自定義函數(shù) /素材 1-100 間素?cái)?shù)from math import sqrt def isprime(x): if x=1: return False k=int(sqrt(x) for j in range(2,k 1): if x%j=0: return False return True for i in range(2,101): if isprime(i): print idef f(x,y=True): #

3、默認(rèn)參數(shù)要放在參數(shù)列表的最后'x and y both correct words or not' print x,'and y both correct' print x,'is Ok' f(68) f(68,False) #傳遞函數(shù) def addme2me(x): return(x x) def self(f,y): print f(y) self(addme2me,2.2) #lambda 函數(shù)my_add=lambda x,y:x y my_add(5,6) #數(shù)據(jù)獲取與表示 f=open(r'E:360Downloadsfir

4、stpro.txt','w') # 新建一個(gè)文件f.write('hello,world') #f 為對(duì)象， write 寫入文件f.close()f=open(r'E:360Downloadsfirstpro.txt','r') #r代表讀出p1=f.read(5) #5 代表讀出的字節(jié)數(shù)p2=f.read()print p1,p2 f.close f1=open(r'E:360Downloadscompanies.txt') cname=f1.readlines() for i in range(0,l

5、en(cname): cnamei=str(i 1) '' cnamei f1.close f2=open(r'E:360Downloadsscompanies.txt','w') f2.writelines(cname) f2.close() #網(wǎng)絡(luò)數(shù)據(jù)獲取 import urllib r=urllib.urlopen(' html=r.read #序列 #標(biāo)準(zhǔn)類型運(yùn)算符 'apple'<'banana' 1,2,3!=4,5,6# 值比較atuple=('ba',126.4) bt

6、uple=atuple btuple is not atuple# 對(duì)象身份比較('86.40'<'122.64') and ('apple'<'banana')#布爾運(yùn)算#序列類型運(yùn)算符 week='mondy','tuesday','wednesday','thursday','firday','sat uday','sunday' print week1,week-2,'n',week1

7、:4,'n',week:6,'n',week:-1#序列值的序號(hào)是從 0 開始到 N-1 或者從 -1 到 N 'apple'*3 'ba' in ('ba','the boeingcompany') #序列類型轉(zhuǎn)換工廠函數(shù) list('hello,world')# 將字符串轉(zhuǎn)成列表tuple('hello,world')# 將字符串轉(zhuǎn)成元組 #字符串 s1='''hello''b'' world!'&#

8、39;' s1 # 三引號(hào)可以保持里面字符串的原貌s2=r'd:pythona.py' s2 ccode='axp','ba','cat','csco','cvx' cprice='86.40','122.64','99.44','23.78','115.91' for i in range(5): print '%d%8s:%8s' %(i,ccodei,cpricei) #%8s 指的占 8

9、個(gè)字符print 'i get %d%!' %32 # 兩個(gè)%會(huì)留下一個(gè)astr='what do you think of this saying 'no pain,no gain'?' tempstr=astr.split(''')1 #' 為轉(zhuǎn)義字符if tempstr.istitle(): print 'it is title format' else: print 'it is not title format'八進(jìn)制數(shù) 000 代表的字符 t 代表橫向制表符print a

10、str# 列表jscores=9,9,8.5,10,7,8,8,9,8,10 ascore=9 jscores.sort() jscores.pop() # 去掉最高分jscores.pop(0) # 去掉最低分jscores.append(ascore) # 合并avescore=sum(jscores)/len(jscores) print avescoreweek='monday','tuesday','wednesday','thursday', 'firday' weekend='saturday

11、','sunday' week.extend(weekend)#extend 合并函數(shù)for i,j in enumerate(week):#enumerate 函數(shù) 產(chǎn)生從 0 開始 的序列print i 1,jnumlist=3,11,5,8,16,1 numlist.sort(reverse=True) # 按逆序排列numlist fruitlist='apple','banana','pear','lemon','avocado' fruitlist.sort(key=len) f

12、ruitlist # 按字符長(zhǎng)度排序#列表解析 x*2 for x in range(10) x*2 for x in range(10) if x*2<50 (x 1,y 1) for x in range(2) for y in range(2) #元組 atruple=(1,2,3) atruple atruple1: len(atruple) btruple=('monday',1,2,3) btruple01 2014, # 創(chuàng)建元組 2014 alist='axp','ba','cat' atruple=(

13、9;axp','ba','cat') alist1='alibaba' atruple1='alibaba'# 元組是不可變的，列表是可變的alist=3,5,2,4 alist.sort() # 改變?cè)瓉砹斜韆list alist=3,5,2,4 sorted(alist) #sorted 只是新生成一個(gè)列表的副本，原來的列 表并沒有改變alist #但元組就只能使用 sorted ，不能用 sort ，因?yàn)椴荒芨淖冊(cè)猘truple=(3,5,2,4) atruple.sort # 會(huì)報(bào)錯(cuò)def func(args1,a

14、rgs2='world'):# 元組作為函數(shù)形式的參數(shù)print args1,args2 func('hello',) func(args2='apple',args1='hello') def func(args1,*args): print args1 print args func('hello,','wangdachui','liuyuan','linlin')#返回值類型為元組的函數(shù) enumerate() 、 coerce()直接#字典 ainfo=

15、9;wangdachui':3000,'niuyun':2000,'linlin':3000 #創(chuàng)建字典info=('wangdachui',3000),('niuyun',2000),('linlin',3000) binfo=dict(info) # 利用 dict 函數(shù)創(chuàng)建字典cinfo=dict('wangdachui',3000,'niuyun',2000,'linlin',3000 ) dinfo=dict(wangdachui=3000,niuy

16、un=2000,linlin=3000) adict=.fromkeys('wangdachui','niuyun','linlin'),3000) #fromkeys 函數(shù)將所有的 keys 初始值設(shè)置為 3000 adict plist=('axp','american express','86.40'),('ba','the boeing company','122.64'),('cat','caterpillar inc

17、.','99.44') alist blist for i in range(2): astr=plisti0 bstr=plisti2 alist.append(astr) blist.append(bstr) adict=dict(zip(alist,blist) #zip 函數(shù)#字典的使用 #字典的基本操作 ainfo='wangdachui':3000,'niuyun':2000,'linglin':4500,'tianq i':8000 ainfo'niuyun' # 鍵值查找ai

18、nfo'niuyun'=9999# 更新ainfo ainfo'funyun'=1000# 查找'mayun' in ainfo # 成員判斷del ainfo # 刪除字典ainfo='wangdachui':3000,'niuyun':2000,'linglin':4500,'tianq i':8000 for key in ainfo.keys():格式說明print 'name=%s,salary=%s' %(key,ainfokey) 'niuyun

19、's salary is %(niuyun)s.' %ainfo #%(key)符 % 字典對(duì)象名ainfo='wangdachui':3000,'niuyun':2000,'linglin':4500,'tianq i':8000 ainfo.keys() ainfo.values() ainfo='wangdachui':3000,'niuyun':2000,'linglin':4500,'tianq i':8000 binfo='wang

20、dachui':3000,'niuyun':9999,'linglin':4500,'wan gzi':8000 ainfo.update(binfo)#update 函數(shù) 快速更改ainfo astock='axp':86.4,'ba':122.64 bstock=astock astock= # 此時(shí)只會(huì)講 astock 清空，不會(huì)將 bstock 清空， 需要用 clear 函數(shù)才會(huì)將關(guān)聯(lián)的都刪除bstock astock.clear() bstock #字典作為函數(shù)的形式參數(shù) def func(ar

21、gs1,*argst,*argsd): # 一個(gè) *是可變長(zhǎng)位置參數(shù)， *可變長(zhǎng)關(guān)鍵字參數(shù) print args1 print argst print argsdfunc('hello','wangdachui','niuyun','linglin',a1=1,a2=2,a 3=3) #集合 names='wangdachui','niuyun','wangzi','wangdachui','lingli ng','niuyun' na

22、messet=set(names) #set 刪除重復(fù)對(duì)象， 因?yàn)榧系脑?都不重復(fù)namesset aset=set('hello') aset fset=frozenset('hello') fset #集合比較 aset=set('sunrise') bset=set('sunset') 'u' in aset aset=bset set('sun') aset&bset # 集合關(guān)系運(yùn)算aset|bset aset-bset asetSset #不能同時(shí)屬于兩個(gè)集合 aset-=s

23、et('sun') # 運(yùn)算符可復(fù)合#集合內(nèi)建函數(shù) aset=set('sunrise') bset=set('sunset') aset.issubset(bset) # 是否為子集ersection(bset) # 交集aset.difference(bset)# 差補(bǔ)cset=aset.copy() # 拷貝#面向可變集合的函數(shù) aset=set('sunrise') aset.add('!') aset aset.update('yeah') aset.remove('

24、;!') aset.clear() #擴(kuò)展庫 scipy import numpy as np xarray=np.ones(3,4) # 生產(chǎn) 3*4 的全部為 1 的矩陣xarry from scipy import linalg arr=np.array(1,2,3,4) linalg.det(arr) #ndarry from numpy import * aarray=array(1,2,3) aarray barray=array(1,2,3),(4,5,6)barray zeros(2,2) arange(1,5,0.5) aarray=array(1,2,3),(4,5

25、,6) sin(aarray) aarray.shape # 數(shù)組的維度barray=aarray.reshape(3,2) barray aarray.sum() aarray.sum(axis=0) # 通過設(shè)置參數(shù)，分別行、列求和aarray.sum(axis=1) carray=array(1,3,5) carray:1 # 切片功能darray=array(2,4,6)函數(shù)函數(shù)earray=array(7,8,9) where(carray>2,darray,earray) #where def fun(x,y): return (x 1)*(y 1) arr=fromfunc

26、tion(fun,(9,9) #fromfunction arr#ufunc 函數(shù)能對(duì)數(shù)組中每個(gè)元素進(jìn)行操作，包括 add 等函數(shù)import numpy as npa=np.arange(1,5) b=np.arange(2,6) np.add(a,b) np.add.accumulate(2,3,8) np.multiply.accumulate(2,3,8) #series #series 類似于一維數(shù)組的對(duì)象，由數(shù)據(jù)和索引組成from pandas import Series import pandas as pd aser=pd.Series(1,2.0,'a') b

27、ser=pd.Series('apple','peach','lemon',index=1,2,3) bser.index bser.values aser'a' import numpy as np np.exp(aser) #series 數(shù)據(jù)對(duì)齊data='axp':'86','csco':'122','ba':'94' sindex='axp','csco','aapl' aser

28、=pd.Series(data,index=sindex) aser pd.isnull(aser)#series 的 name 屬性='cnames ='volume' aser #dataframe 表結(jié)構(gòu)#大致可以看成共享一個(gè) index 的 series 的集合data='name':'wangdachui','linlin','niuyun','pay':4000,500 0,6000 frame=pd.DataFrame(data)

29、 frame'name' frame.pay frame.ix2 # 索引所對(duì)應(yīng)的數(shù)據(jù)#dataframe 對(duì)象的修改和刪除frame'name'='admin' # 對(duì) name 下的所有元素進(jìn)行更改del frame'pay' frame ='no' #便捷數(shù)據(jù)獲取 #便捷網(wǎng)絡(luò)數(shù)據(jù) 雅虎財(cái)經(jīng)from matplotlib.finance import quotes_historical_yahoo from datetime import date import pandas a

30、s pdtoday=date.today() start=(today.year-1,today.month,today.day) quotes=quotes_historical_yahoo('AXP',start,today) df=pd.DataFrame(quotes) print df #自然語言工具包 NLTK from nltk.corpus import gutenberg import nltk print gutenberg.fileids() #數(shù)據(jù)準(zhǔn)備 from matplotlib.finance import quotes_historical_ya

31、hoo from datetime import date import pandas as pd today=date.today() start=(today.year-1,today.month,today.day) quotes=quotes_historical_yahoo('AXP',start,today) fields='date','open','close','high','low','volume' quotesdf=pd.DataFrame(quotes,co

32、lumns=fields) # 通過columns 數(shù)據(jù)加屬性名quotesdf=pd.DataFrame(quotes,index=range(1,len(quotes) 1,columns=fields) print quotesdffrom datetime import date from datetime import datetime y=datetime.strftime(x,'%Y-%m-%d') # 將日期轉(zhuǎn)換成固定格import pandas as pd dates=pd.date_range('20141001',periods=7) #

33、自己創(chuàng)建時(shí) 間序列dates #數(shù)據(jù)顯示 djidf.index djidf.columns djidf.values djidf.describe# 顯示數(shù)據(jù)描述djidf.head(5)# 顯示前五行數(shù)據(jù)djidf.tail(5)可以使#數(shù)據(jù)選擇 quotesdfu'2013-12-02':u'2013-12-06' #dataframe用索引選擇djidf'code' djidf.loc1:5, # 通過 loc 通過標(biāo)簽選擇數(shù)據(jù)， 第一個(gè)參數(shù)是行 標(biāo)簽，第二個(gè)參數(shù)是列標(biāo)簽djidf.loc:,'code','las

34、ttrade' # 前面這個(gè)：需要djidf.loc1:6,0,2 # 通過的行位置，列位置選擇標(biāo)簽quotesdfquotesdf.index>=u'2014-01-01' quotesdf(quotesdf.index>=u'2014-01-01')&(quotesdf.close >=95)# 條件篩選#簡(jiǎn)單統(tǒng)計(jì)預(yù)處理 djidf.mean(columns='lasttrade')# 最近一次成交價(jià)的平均值djidfdjidf.lasttrade>=120.name# 最近一次成交價(jià)大于等于股票漲的天相鄰兩天數(shù)120 的公司名len(quotesdfquotesdf.close>quotesdf.open) # len(q