创建一个在文件各行中查找匹配子串的生成器
>>> def filematch(filename, substr): with open(filename, 'r') as f: for line in f: if substr in line: yield line >>> for line in open('Data/portfolio.csv'): print(line, end='') name,shares,price "AA",100,32.20 "IBM",50,91.10 "CAT",150,83.44 "MSFT",200,51.23 "GE",95,40.37 "MSFT",50,65.10 "IBM",100,70.44 >>> for line in filematch('Data/portfolio.csv', 'IBM'): print(line, end='') "IBM",50,91.10 "IBM",100,70.44 >>>