- 打开文件的常用代码
import os os.getcwd() #获取当前工作目录 os.chdir('../HeadFirstPython/chapter3') #切换到指定文件夹 data = open('sketch.txt') for each_line in data: print(each_line,end=' ') data.close()
- Python字符串的split()与find()函数
data = open('sketch.txt') for each_line in data: if not each_line.find(':') == -1: #如果each_line中有“:”则返回该子串在原字符串中的索引,如果无法找到则返回-1 (role,line_spoken) = each_line.split(':',1) #此为多重赋值,以“:”作字符串分割,1的含义是以将字符串分割为两部分 print(role,end=' ') print(' said: ',end=' ') print(line_spoken,end=' ') data.close()
- Try/except机制
try: 需要保护的代码,可能会导致一个运行时错误 except: 错误恢复代码
try: data = open('sketch.txt') for each_line in data: try: (role,line_spoken) = each_line.split(':',1) print(role,end=' ') print(' said: ',end=' ') print(line_spoken,end=' ') except: pass #如果split调用出现问题,则使用pass继续执行代码(可以把pass认为是空语句或者null语句) data.close() except: print('The data file is missing!') #一旦文件未找到,则执行这句
使用异常机制可以让你关注代码真正需要做的工作……