var = 100 if var == 100: print("变量 var 的值为100") del var # Python has special "while ... else ..." condition count = 0 while count < 5: print(count, " is less than 5") count = count + 1 else: print(count, " is not less than 5") del count var1 = var2 = 'Hello World!' var2 = var1[:6] + 'Runnob!' print("Renew String :- {}{}", var1[:6] + 'Runoob!') print("var1 charset:- ", var1) print("var2 charset:- ", var2) del var1, var2 print("My name is %s and weight is %d kg!" % ('Zara', 21)) # Unicode # print(u'Hello\u0020 \u0028 \u0029 World!') # print(u"\u7f8e\u8f1d\u8857\uff0c\u7f8e\u7530\u90a8") # print(u"\u571f\u74dc\u7063\u7f8e\u666f\u885755\u865f\u5b89\u5eb7\u5927\u5ec8\u4e00\u6a13b\u5ba4") # print(u"\u4e5d\u9f8d\u4f55\u6587\u7530\u5fe0\u5b5d\u885760\u865f\u611b\u6c11\u90a8\u980c\u6c11\u6a1317\u6a131719\u5ba4 Hong Kong") import time def printTime(): return "Current time is: %s" % (time.strftime("%Y-%m-%d" ,time.localtime(time.time()))) print(printTime()) # input([prompt]) 函数从标准输入读取一个行,并返回一个字符串(去掉结尾的换行符): # string = input("请问你叫什么名字? ") # print("原来你是 %s 阿!" % string) # del string # input([prompt]) 函数和 input([prompt]) 函数基本类似,但是 input 可以接收一个Python表达式作为输入,并将运算结果返回。 # 请输入:[x*5 for x in range(2,10,2)] # 你输入的内容是: [10, 20, 30, 40] # string = input("请输入列表组") # print(string) # fo = open('/Users/tsuyuhsia/Desktop/Practice/ajax_info.txt', "r") # print("文件名: ", fo.name) # print("是否已关闭 : ", fo.closed) # print("访问模式 : ", fo.mode) # print("末尾是否强制加空格 : ", fo.softspace) # 如果用print输出后,必须跟一个空格符,则返回false。否则返回true。 # fi = open('/Users/tsuyuhsia/Desktop/Practice/ajax_info.txt2', "w+") # # fi.write(fo.read(20)) # fi.write(fo.read()) # # position = fo.tell() # print("当前文件位置 : ", position) # position = fo.seek(0, 0) # fi.write(fo.read(21)) # # fo.close() # print("是否已关闭 : ", fo.closed) ## Exception 异常处理 ## try: fh = open("testfile", "w") # fh = open("testfile", "r") try: fh.write("这是一个测试文件,用于测试异常!!") finally: print("关闭文件") fh.close() except IOError: # 截取一个或是多个异常 print("[Error]: 没有找到文件或读取文件失败") # print(e # print("-------" except: # Capture all errors print("[Error]: Unknown error occures") else: print("[Else]: No error occurs") finally: print("[Finally]: Try blocks end") import os os.remove("testfile") # 定义函数 def temp_convert(var): try: return int(var) except ValueError as Argument: # 一个异常可以带上参数,可作为输出的异常信息参数。 print("Parameter doesn't have number: \n[%s]" % Argument) temp_convert("abc"); # 调用函数 # 定义函数 print("------") def mye(level): if level < 1: raise Exception("Invalid level! Err...", level) # 触发异常后,后面的代码就不会再执行 try: # mye(0) # 触发异常 mye(2) # 触发异常 except "Invalid level! Err..": print(1) else: print(2) print("------") ''' * 用户自定义异常 通过创建一个新的异常类,程序可以命名它们自己的异常。异常应该是典型的继承自Exception类,通过直接或间接的方式。 以下为与RuntimeError相关的实例,实例中创建了一个类,基类为RuntimeError,用于在异常触发时输出更多的信息。 在try语句块中,用户自定义的异常后执行except块语句,变量 e 是用于创建Networkerror类的实例 ''' class myPythonError(RuntimeError): def __init__ (self, arg): self.args = arg try: raise myPythonError('Nothing') except myPythonError as e: print("Customize Error") print(e.args) else: print('Nothing happened') # 文档重新命名 # os.rename('/Users/tsuyuhsia/Desktop/Practice/ajax_info.txt2', '/Users/tsuyuhsia/Desktop/Practice/ajax_info.txt3') # os.remove() # os.mkdir() # os.rmdir() # os.chdir() # os.getcwd() # A newer way to format strings is the format method. # This method is the preferred way print("{} is a {}".format("This", "placeholder")) print("{0} can be {1}".format("strings", "formatted")) # You can use keywords if you don't want to count. print("{name} wants to eat {food}".format(name="Bob", food="lasagna"))