編程的生活愈發(fā)不容易了，工作越來越難找，說多了都是淚還是給大家貢獻(xiàn)些代碼比較實(shí)際。

python3 鏈接數(shù)據(jù)庫需要下載名為pymysql的第三方庫

python3 讀寫xlsx需要下載名為openpyxl的第三方庫

在此我只貢獻(xiàn)鏈接數(shù)據(jù)庫和寫入xlsx的代碼

import pymysql.cursorsfrom fj.util import loggerfrom openpyxl import Workbookfrom openpyxl.compat import rangefrom openpyxl.utils import get_column_letter # 鏈接數(shù)據(jù)庫的游標(biāo)connect = pymysql.Connect( host='localhost', port=3306, user=’root’, passwd=’123456’, db=’zyDB’, charset=’utf8’,)cursor = connect.cursor() # 關(guān)閉數(shù)據(jù)庫鏈接操作def clos_cursor(): return cursor.close(); # 讀取數(shù)據(jù)庫數(shù)據(jù)def query_all(): select_sql = 'select*from fj_date where fj_id not in' '( select a.fj_id from ( select * from fj_date where mj_id>0 ) a ' 'join ( SELECT * from fj_date where jb_id>0 ) b' ' on a.fjzz = b.fjzz and a.fj_add=b.fj_add) and mj_id>0' cursor.execute(select_sql); return cursor.fetchall(); # 關(guān)閉數(shù)據(jù)庫鏈接操作def clos_cursor(): cursor.close(); connect.close() def read_mysql_to_xlsx(): #要?jiǎng)?chuàng)建的xlsx名稱 dest_filename = ’jb_data.xlsx’ wb = Workbook() ws1 = wb.active ws1.title = 'fj_date' # 列名 ws1.cell(row=1,column=1,value='fj_id(數(shù)據(jù)庫編號)') ws1.cell(row=1,column=2,value='jb_id(疾病編號)') ws1.cell(row=1,column=3,value='mj_id(名醫(yī)編號)') ws1.cell(row=1,column=4,value='fj_name(方劑名稱)') ws1.cell(row=1,column=5,value='fjcc(出處)') ws1.cell(row=1,column=6,value='fjdm(代碼)') ws1.cell(row=1,column=7,value='fjzc(加減)') ws1.cell(row=1,column=8,value='fjgx(功效)') ws1.cell(row=1,column=9,value='fj_add(組成)') ws1.cell(row=1,column=10,value='fjjj(禁忌)') ws1.cell(row=1,column=11,value='fjzy(方劑治驗(yàn))') ws1.cell(row=1,column=12,value='fjzz(主治)') ws1.cell(row=1,column=13,value='fjyf(用法)') ws1.cell(row=1,column=14,value='ylzy(藥理作用)') ws1.cell(row=1,column=15,value='gjls(各家論述)') ws1.cell(row=1,column=16,value='fj(方解)') ws1.cell(row=1,column=17,value='ks(科室)') ws1.cell(row=1,column=18,value='ckzl(參考資料)') ws1.cell(row=1,column=19,value='lcyy(臨床應(yīng)用)') ws1.cell(row=1,column=20,value='tjbq(推薦標(biāo)簽)') ws1.cell(row=1,column=21,value='zysx(注意事項(xiàng))') ws1.cell(row=1,column=22,value='fjzb(制備方法)') ws1.cell(row=1,column=23,value='fg(方歌)') ws1.cell(row=1,column=24,value='path(路徑)') # 循環(huán)數(shù)據(jù)寫入內(nèi)容 jb_date_list = query_all() for i in range(2,len(jb_date_list)+1): ws1.cell(row=i, column=1, value=jb_date_list[i-1][0]) ws1.cell(row=i, column=2, value=jb_date_list[i-1][1]) ws1.cell(row=i, column=3, value=jb_date_list[i-1][2]) ws1.cell(row=i, column=4, value=jb_date_list[i-1][3]) ws1.cell(row=i, column=5, value=jb_date_list[i-1][4]) ws1.cell(row=i, column=6, value=jb_date_list[i-1][5]) ws1.cell(row=i, column=7, value=jb_date_list[i-1][6]) ws1.cell(row=i, column=8, value=jb_date_list[i-1][7]) ws1.cell(row=i, column=9, value=jb_date_list[i-1][8]) ws1.cell(row=i, column=10, value=jb_date_list[i-1][9]) ws1.cell(row=i, column=11, value=jb_date_list[i-1][10]) ws1.cell(row=i, column=12, value=jb_date_list[i-1][11]) ws1.cell(row=i, column=13, value=jb_date_list[i-1][12]) ws1.cell(row=i, column=14, value=jb_date_list[i-1][13]) ws1.cell(row=i, column=15, value=jb_date_list[i-1][14]) ws1.cell(row=i, column=16, value=jb_date_list[i-1][15]) ws1.cell(row=i, column=17, value=jb_date_list[i-1][16]) ws1.cell(row=i, column=18, value=jb_date_list[i-1][17]) ws1.cell(row=i, column=19, value=jb_date_list[i-1][18]) ws1.cell(row=i, column=20, value=jb_date_list[i-1][19]) ws1.cell(row=i, column=21, value=jb_date_list[i-1][20]) ws1.cell(row=i, column=22, value=jb_date_list[i-1][21]) ws1.cell(row=i, column=23, value=jb_date_list[i-1][22]) ws1.cell(row=i, column=24, value=jb_date_list[i-1][23]) # 創(chuàng)建xlsx wb.save(filename=dest_filename) if __name__ == ’__main__’: read_mysql_to_xlsx()

補(bǔ)充知識：Python 關(guān)閉文件釋放內(nèi)存的疑惑

我用with語句打開了一個(gè)4g的文件讀取內(nèi)容，然后程序末尾設(shè)置一個(gè)死循環(huán)，按理說with語句不是應(yīng)該自動(dòng)關(guān)閉文件釋放資源嗎？

但是系統(tǒng)內(nèi)存一直沒有釋放。應(yīng)該是被文件讀取到的變量content一直占用嗎？把content刪除就會(huì)釋放內(nèi)存。或者去掉死循環(huán)，程序退出資源就自動(dòng)釋放了

既然這樣的話關(guān)閉文件貌似沒啥作用呢？具體釋放了什么資源？

Python一直占用著將近5G的內(nèi)存：

官方文檔：

If you’re not using the with keyword, then you should call f.close() to close the file and immediately free up any system resources used by it. If you don’t explicitly close a file, Python’s garbage collector will eventually destroy the object and close the open file for you, but the file may stay open for a while. Another risk is that different Python implementations will do this clean-up at different times.

After a file object is closed, either by a with statement or by calling f.close(), attempts to use the file object will automatically fail.

代碼如下：

import syswith open(r’H:BaiduNetdiskDownload4K.mp4’,’rb’) as f: print(f.closed) content=f.read()print(f.closed)print(sys.getrefcount(f))while True: pass

以上這篇python3 使用openpyxl將mysql數(shù)據(jù)寫入xlsx的操作就是小編分享給大家的全部內(nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持好吧啦網(wǎng)。