Python 学习系列（四）
这篇文章继续介绍Python的IO内建函数，下面是我做的一个Sample:'''Created on 2010-4-4@author: Jamson Huang'''#解析字符串函数以及IO函数import sys#import osimport mathif __name__ == '__main__': #gloabal zone a = 5 count = 0 tempStr = ['homework','something', 'python','jamson'] tempZip = ['Children', 'do', 'Male', 'user'] myDicts = {('China','Hubei'):('yourName','Jamson')} tempTable = {'china':86,'singpore':65} globalStr = 'python is loved language!' filePath = 'C:/python/mylog.txt' #string function #注意：当全局变量和局部变量相同时，会出现error:UnboundLocalError def strFunc(): print('repr():', repr(globalStr)) print('repr():', repr(0.1)) print(globalStr.zfill(50)) print('we are the {0} who says {1}'.format('chinese', 'chinese')) print('The value of PI is approximately {0:.4f}'.format(math.pi)) for countryStr,zipStr in tempTable.items(): print('{0:10}=>{1:10d}'.format(countryStr, zipStr)) tempTable1 = {'china':'jamson', 'singapore':'Liew Sig'} for countryStr,personStr in tempTable1.items(): print('{0:10}=>{1:s}'.format(countryStr, personStr)) myFile = open(filePath,'r') for line in myFile: print(line, end='') strFunc() #readline 和readlines的不同 #tell():方法返回一个指代文件对象当前位置的整数，表示从文件开头到当前位置的字节数。 #seek(offset, from_what):新的位置是通过将 offset 值与参考点相加计算得来的， # 参考点是由 from_what 参数确定的。 如果 from_what 值为0则代表从文件头开始计算， # 值为1时代表从当前文件位置开始计算，值为2时代表从文件尾开始计算。 from_what 参数 # 可以省略并且其默认值为0，即使用文件头作为参考点 def fileIoFunc(): myFile = open(filePath,'rb+') print(myFile.readline())#注意大小写 print(myFile.tell()) print(myFile.seek(10)) print(myFile.tell()) print(myFile.seek(11,1)) print(myFile.tell())# print(myFile.size())# print(myFile.readlines()) myFile.close()# myFile.read() try: myFile.read() except ValueError: print(sys.stderr, 'IO Read Error') finally: print('IO read close') #Traceback (most recent call last): #File "<stdin>", line 1, in ? #ValueError: I/O operation on closed file fileIoFunc() #with key in file IO:这个方法在很多高级语言中都使用(如java) #open(filename, mode) # 通常，文件是以 text mode （文本模式）方式打开， # 即你从文件中读写字符串都是以一种特殊编码（默认为UTF-8）进行编码的。 可以通过在常用模式后添加 'b' # 选项从而以 binary mode （二进制模式）打开文件，现在数据就是以字节码对象形式来读写了。 # 这种模式可以用在所有非文本文件中,例如:jpeg图片。 def withFunc(): with open(filePath, 'r') as f: print(f.read()) f.close() withFunc() #pickle():pickling and unpickling # 它几乎可以将任何Python对象（甚至是一些Python代码！）转换为字符串表示形式，这个过程称为 # pickling （封装）。 从这个字符串表示形式中重建Python对象被称为 unpickling （拆封）。 # 在 pickling 和 unpickling 之间，字符串表示的对象可以存储在文件或数据中， # 或者可以通过网络连接发送给远程的机器。被称为persistent 对象（持久化对象） import pickle def pickleFunc(): x = '' with open(filePath, 'r') as f: x = pickle.load(f) print(x)# pickle.dump(x, f)
Run Python， Console输出结果为:
repr(): 'python is loved language!'repr(): 0.10000000000000000000000000python is loved language!we are the chinese who says chineseThe value of PI is approximately 3.1416singpore=> 65china => 86china =>jamsonsingapore =>Liew SigIf you do much work on computers, eventually you find that there’s some task you’d like to automate. For example, you may wish.b'If you do much work on computers, eventually you find that there\xa1\xaf\r\n'6810102121<_io.TextIOWrapper name='<stderr>' encoding='UTF-8'> IO Read ErrorIO read closeIf you do much work on computers, eventually you find that there’s some task you’d like to automate. For example, you may wish.
页:
[1]