lt = [ {'name':'小王', 'age':18, 'info':[('phone', '123'), ('dizhi', '广州')]}, {'name':'小芳', 'age':19, 'info':[('phone', '789'), ('dizhi', '深圳')]}, {'name':'小杜', 'age':22, 'info':[('phone', '567'), ('dizhi', '北京')]}, {'name':'小孟', 'age':28, 'info':[('ph