user:

1,aaa,11,mi1,miboy
2,bbb,22,mi2,miboy
3,ccc,33,mi3,miboy
4,ddd,44,mi4,miboy

column_dic = {‘id‘:0,‘name‘:1,‘age‘:2,‘phone‘:3,‘job‘:4}

def filter_handler(operate,con):
    ‘‘‘
    進行篩選工作
    :param operate:用戶輸入的操作
    :param con:用戶輸入的條件
    :return:被選中的所有行組成的列表，每一個都是一個列表
    ‘‘‘
    selected_lst = []
    col,val = con.split(operate)
    col = col.strip()
    val = val.strip()
    judge = ‘int(line_lst[column_dic[col]]) %s int(val)‘%operate if operate == ‘>‘ or operate == ‘<‘ else ‘line_lst[column_dic[col]]%s val‘%operate
    f = open(‘users‘,encoding=‘utf-8‘)
    for line in f:
        line_lst = line.strip().split(‘,‘)
        if eval(judge):
            selected_lst.append(line_lst)
    f.close()
    return selected_lst



def get_selected_line(con):
    ‘‘‘
    獲取要查找的行，並將每一行作為一個列表存儲在selected_list中
    :param con:用戶輸入的查找條件
    :return:符合條件的行的列表
    ‘‘‘
    if ‘>‘ in con:
        selected_list = filter_handler(‘>‘,con)
    elif‘<‘ in con:
        selected_list = filter_handler(‘<‘,con)
    elif‘=‘ in con:
        selected_list = filter_handler(‘==‘,con.replace(‘=‘,‘==‘))
    elif ‘like‘ in con:
        selected_list = filter_handler(‘in‘,con)
    return selected_list



def get_show_list(col_condition):
    ‘‘‘
    獲取要展示的列名
    :param col_condition: 用戶輸入的select條件
    :return:列名組成的字典
    ‘‘‘
    col_info_lst = col_condition.strip().split(‘select‘)
    col_info_lst = [col_info_item for col_info_item in col_info_lst if col_info_item.strip()]
    if col_info_lst:
        col_info = col_info_lst[0].strip()
        if col_info == ‘*‘:
            return column_dic.keys()
        elif col_info:
            ret = col_info.split(‘,‘)
            return [item.strip() for item in ret]
        else:print(con_info)



def show(selected_lst,show_lst):
    ‘‘‘
    展示符合條件的內容
    :param selected_lst: 符合條件的行的列表
    :param show_lst: 所有要展示的字段
    :return: None
    ‘‘‘
    for selected_item in selected_lst:
        for col in show_lst:
            print(selected_item[column_dic[col]],end = ‘ ‘)
        print() #打印回車



condition = input(‘請輸入：‘)
ret = condition.split(‘where‘)
con = ret[1].strip()
show_lst = get_show_list(ret[0])
selected_lst = get_selected_line(con)
show(selected_lst,show_lst)

python學習筆記(26) 員工信息表