python基础七--异常处理

try:
    5/0
except Exception as e:   #这个exception 能捕捉到所有的异常
    print(‘异常信息：‘,e)     #这个是出了异常的话，怎么处理，e代表异常信息
else:
    print(‘没有出异常的话，走这里‘)   #若是没有出现异常，运行else
finally:
    print(‘这里是finally‘)   #无论是否出现异常，都会执行finally

def is_float(s):
    try:
        float(s)
    except Exception as e:
        return False
    return True

res=is_float(-1.2)
print(res)

import pymysql

def OpertionMysql(host,user,passwd,db,sql,port=3306,charset=‘utf8‘):
    try:
        conn = pymysql.connect(host=host,user=user,passwd=passwd,port=port,db=db,charset=charset)   #建立连接
    except Exception as e:
        return {"code":308,"msg":"数据库连接异常%s"%e}
    cur = conn.cursor(cursor=pymysql.cursors.DictCursor)    #建立游标
    try:
        cur.execute(sql)   #执行sql
    except Exception as e:
        return {"code":309,"msg":"sql错误！%s"%e}
    else:
        if sql.startswith(‘select‘):  # 判断是什么语句
            res = cur.fetchone()
        else:
            conn.commit()
            res = 88
        return res
    finally:
        cur.close()
        conn.close()

res = OpertionMysql(‘192.168.160.3‘,‘root‘,‘123456‘,‘hqtest‘,‘xxxxxx‘)
print(res)