9-day9-大作业-生成器

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Q1mi"
# Date: 2017/6/16

# 实现tail | grep 功能

import time

def tail(filename):
    with open(filename, 'r', encoding='utf-8') as f:
        f.seek(0, 2)
        while True:
            line = f.readline()
            if line:
                yield line
            else:
                time.sleep(0.3)


def grep(lines, pattern):
    print('lines', lines)
    for line in lines:
        if pattern in line:
            print(line)

g = tail('a.txt')

grep(g, 'error')


# 设计实现 tail + grep + grep

import time

def tail(filename):
    with open(filename, 'r', encoding='utf-8') as f:
        f.seek(0, 2)
        while True:
            line = f.readline()
            if line:
                yield line
            else:
                time.sleep(0.4)


t = tail('a.txt')


def grep(lines, pattern):
    for line in lines:
        if pattern in line:
            yield line


g = grep(t, 'alex')

g_2 = grep(g, '3714')

for xx in g_2:
    print(xx)


# 2 文件b.txt内容
# apple 10 3
# tesla 100000 1
# mac 3000 2
# lenovo 30000 3
# chicken 10 3
#
# 要求使用列表解析，从文件a.txt中取出每一行，做成下述格式
# [{‘name’:'apple','price':10,'count':3},{...},{...},...]

with open("b.txt", "r", encoding="utf-8") as f:
    for line in f:
        print([{'name':  line.strip().split()[0], 'price':line.strip().split()[1], 'count':line.strip().split()[2]} for line in f])
        for i in [{'name':line.strip().split()[0],'price':line.strip().split()[1],'count':line.strip().split()[2]} for line in f]:
         print(i)


# 4.周末大作业
# 周末大作业（见图）：
#     只实现作业要求的查询功能
#     增加，删除，修改功能为选做题

# 周末大作业
# SQL 1：select name,age from staff_table where age > 22
# SQL 2：select * from staff_table where dept = IT
# SQL 3：select * from staff_table where enroll_date like 2013
import os
def search(sql):

    sql_split_list = sql.split(" ")
    staff_info_keys = ["staff_id", "name", "age", "phone", "dept", "enroll-date"]
    if sql == ('select name,age from staff_table where age > %s' %(sql_split_list[7])):
                with open('abc.txt', 'r', encoding="utf-8") as f:
                    list = []
                    for line in f:
                        i = line.strip().split(",")
                        name_age_list = [i[1], i[2]]
                        if i[2] > sql_split_list[7]:
                            list.append(name_age_list)
                    for i in list:
                        print(i)
                    print("%s row in set" %len(list))
    elif sql == ('select * from staff_table where %s like %s' % (sql_split_list[5],(sql_split_list[7]))):
        with open('abc.txt', 'r', encoding="utf-8") as f:
            list = []
            for line in f:
                i = line.strip().split(',')
                j = i[5].split('-')
                if j[0] == sql_split_list[7]:
                    list.append(i)
            for x in list:
                print(x)
            print("%s row in set" %len(list))
    else:
        with open('abc.txt', 'r', encoding="utf-8") as f:
            list = []
            for line in f:
                i = line.strip().split(",")
                if sql == ('select * from staff_table where %s = %s' % (sql_split_list[5], i[(staff_info_keys.index(sql_split_list[5]))])):
                        list.append(i)
                else:
                    continue
            for j in list:
                 print(j)
            print("%s row in set" %len(list))

tag = True
while tag:
    sql = input("请输入SQL语句(q quit)： ").strip()
    if sql != 'quit':
        search(sql)
    else:
        tag = False