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I. Design requirements

1. Add a book

two。 Query data

3. Borrow books

Storage mode, save to hard disk with excel or save with .txt file

Second, implementation code

1. Use excel to store

# 1. Introduce # main functions # 1, borrow books # 2, add new books # 3, find books # data storage: excel table import xlwtimport xlrdimport xlutils.copyimport os#book = {"location", "title": "," Price "," author ":"} # Storage method: exceltitle = [location "," title "," Price "," author "] # View the current number of books Line number def read_book_num (): path = os.path.join (os.getcwd () + r'\ Books .xls') print (path) flag = os.path.exists (path) if (flag): book_excel = xlrd.open_workbook ("Books .xls") sheet1 = book_excel.sheets () [0] book_num = sheet1.nrows else: book_num = 0 return book_numdef add_book (book_num): # determine whether excel exists If it doesn't exist, Just create path = os.path.join (os.getcwd () + r'\ Books .xls') flag = os.path.exists (path) print ("flag", flag) if (flag): # if it exists Just open excel book_excel = xlrd.open_workbook ("Book .xls") # and copy the existing data book_excel = xlutils.copy.copy (book_excel) sheet1 = book_excel.get_sheet (0) # sheet1 = book_excel.sheets () [0] else: book_excel = xlwt.Workbook ("Book .xls") # New Build excel sheet1 = book_excel.add_sheet (sheetname= "Book form") Cell_overwrite_ok=True) while (1): # print prompt button_num = input ("Please select your operation\ n:" + "1. Add new book\ n "+" 2. To exit, press Q\ n ") if (button_num = ='q'): break elif (button_num = =" 1 "): # enter all the information about a book And first store it in book book = [] # empty book information input_value =''# empty input for i in range (4): print ("Please enter:" Title [I]) input_value = input () book.append (input_value) # Storage to hard disk (store input data in excel) for i in range (4): # write to the book _ num line data sheet1.write (book_num,i Book [I]) book_num = book_num + 1 # Total number of books plus 1 book_excel.save ("Books .xls") print ("added successfully") else: print ("invalid input" Please re-enter! ") Def search_book (): # Open excel book_excel = xlrd.open_workbook ("Books .xls") sheet1 = book_excel.sheets () [0] book_num = sheet1.nrows while (1): # enter the title of the book chose= input ("Please enter your action:\ n" + "1. Query books:\ n "+" 2. To exit, please press Q\ n ") if (chose = ='q'): break elif (chose = ='1'): bookname = input (" Please enter the title of the book: ") for i in range (0bookbookkeeper num): if (bookname = = sheet1.cell (iMagn0) .value): print (" query succeeded " The query result is\ n ", sheet1.row_values (I)) return else: print (" query failed, there is no such book in this library ") return else: print (" incorrect operation, please re-enter! ") Def borrow_book (): # Open excel book_excel = xlrd.open_workbook ("Books .xls") sheet1 = book_excel.sheets () [0] book_num = sheet1.nrows book_excel_copy = xlutils.copy.copy (book_excel) sheet1_copy = book_excel_copy.get_sheet (0) # re-create an excel Used to save updated data # book_excel_new = xlwt.Workbook ("Book .xls") # New excel # sheet1_new = book_excel_new.add_sheet (sheetname= "1", cell_overwrite_ok=True) while (1): # enter the title of the book print ("1. Please enter the title of the borrowed book\ n2. Press Q to exit the book borrowing interface ") bookname = input () if (bookname = ='q'): return else: # find a = 0 for i in range (0, book_num): if (bookname = = sheet1.cell (I) 0) .value): for j in range (4): a = I + 1 while (book_num-a): sheet1_copy.write J) .value) # clear location a + = 1 print ("borrowed successfully") book_excel_copy.save ('book .xls') return # else: # a = I # sheet1_copy.write (I JJM sheet1.cell (a) J) .value) # clear location # book_excel_copy.save ('book .xls') if _ _ name__ ='_ _ main__': book_num = read_book_num () print (book_num) while (1): print ("* library management system *) print (" * 1. Add a new book * ") print (" * 2. Query books * ") print (" * 3. Borrow books * ") print (" * 4. Exit * ") op = input (" Please enter your operation: ") if (op = =" 1 "): add_book (book_num) elif (op = =" 2 "): search_book () elif (op = =" 3 "): borrow_book () elif (op = =" 4 "): Break else: print ("invalid input Please re-enter! ")

two。 Store in txt file mode

Def add_book (): file = open ("Library Management system .txt", "a +") print ("Please enter the book information to add:") id = input ("id:") name = input ("bookname:") author = input ("author:") # table = [name,id,author] file.write (id+ "" + name+ "" + author+ "\ r") print ("Book added successfully!") File.close () def serch_book (): file = open ("Library Management system .txt" "r") name = input ("Please enter the title of the book to be queried:") read_data_all = [] count = len (file.readlines ()) # print (count) file.seek (0P0) # move the file pointer to the beginning for i in range (count): read_data = file.readline (). Split () read_data_all.append (read_data) For read_data in read_data_all: # print (type (read_data)) if (name==read_data [0]): print ("the data information queried is:" Read_data) break else: print ("failed to find") file.close () return read_datadef borrow_book (): file = open ("Library Management system .txt", "r +") # find out whether the book exists first If it exists, lend count = len (file.readlines ()) read_data_all= [] file.seek (0Let0) # you need to move the file pointer to the beginning for i in range (count): read_data = file.readline (). Split () read_data_all.append (read_data) print (read_data_all) file.close () book = serch_book () File = open ("Library Management system .txt" "w") for line in read_data_all: if book==line: continue line_to_str =''.join (line) # convert the list into a string file.write (line_to_str+ "\ n") if _ _ name__ = = "_ _ main__": # open directly open a file If the file does not exist, create the file while (1): print ("* Library Management system *") print ("* 1. Add a new book * ") print (" * 2. Query books * ") print (" * 3. Borrow books * ") print (" * 4. Exit * ") op = input (" Please enter your operation: ") if (op = =" 1 "): add_book () elif (op = =" 2 "): serch_book () elif (op = =" 3 "): borrow_book () else: break or above It is about the content of the article "how to implement a simple Library Management system in python". I believe we all have a certain understanding. I hope the content shared by the editor will be helpful to you. If you want to know more about the relevant knowledge, please pay attention to the industry information channel.

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