To je StringIO modul je objekt v pamäti podobný súboru. Môže sa použiť na vstup alebo výstup väčšiny funkcií, ktoré môžu používatelia očakávať od bežného súborového objektu. Keď používateľ vytvorí objekty StringIO, najprv sa vytvorí poskytnutím reťazca konštruktorovi. Ak tam nie je žiadny reťazec, StringIO bude prázdny. V oboch prípadoch bude pôvodne zobrazený kurzor na súbore začínať na nule.
Modul nie je dostupný v najnovšej verzii Pythonu; teda, aby sme mohli používať tento modul, musíme ho preniesť do modulu Io v Pythone vo forme io.StringIO.
Príklad:
# First, we will import the required module. from io import StringIO as SIO # The arbitrary string. string_1 = 'This is the initialized string.' # Here, we will use the StringIO method for setting as the file object. # Now, we have an object-file that we can treat as a file. file_1 = SIO(string_1) # Now, we will be reading the file by using read() print (file_1.read()) # Here, We can also write in this file. file_1.write(' Welcome to Javatpoint.com.') # by using the following command, we can make the cursor at index 0. file_1.seek(0) # by using the following command, the user is able to print the file after writing #in the initialized string (string_1). print ('The file of the string after writing in it is:', file_1.read())
Výkon:
This is the initialized string. The file of the string after writing in it is: This is the initialized string. Welcome to Javatpoint.com.
Dôležité metódy StringIO:
Nasleduje niekoľko metód StringIO:
1. StringIO.getvalue(): Táto funkcia sa používa na vrátenie celého obsahu súboru.
Syntax:
Syntax vyššie uvedenej metódy je:
File_name.getvalue()
Príklad:
# First, we will import the StringIO module. from io import StringIO as SIO # The arbitrary string. string_1 = 'Hello and thank you for visiting to Javatpoint.com.' # Here, we will use the StringIO method for setting as the file object. file_1 = SIO(string_1) # Retrieving the complete contents of the above file. print(file_1.getvalue())
Výkon:
staviteľ strún
Hello and thank you for visiting to Javatpoint.com
2. V tomto sa pozrieme na niektoré funkcie StringIO, ktoré vracajú boolovskú hodnotu, t. j. buď nepravdu alebo pravdivú:
Syntax:
Syntax vyššie uvedenej metódy je:
1. File_name.isatty() 2. File_name.readable() 3. File_name.writable() 4. File_name.seekable() 5. File_name.closed
Príklad:
# First, we will import the StringIO module. from io import StringIO as SIO # The arbitrary string. string_1 = 'Hello and thank you for visiting to Javatpoint.com.' # Here, we will use the StringIO method for setting # as the file object. file_1 = SIO(string_1) # by using the following command, the user will be able to return is the file #interactive or not. print ('Is the file stream above interactive?', file_1.isatty()) # by using the following command, # the user will be able to return is the file readable or not. print ('Is the file stream above readable?', file_1.readable()) # by using the following command, # the user will be able to return does the file support writing or not. print ('Is the file stream above writable?', file_1.writable()) # by using the following command, , the user will be able to return is the file #seekable or not. print ('Is the file stream above seekable?', file_1.seekable()) # by using the following command, the user will be able to return is the file #closed or not. print ('Is the file above closed?', file_1.closed)
Výkon:
Is the file stream above interactive? False Is the file stream above readable? True Is the file stream above writable True Is the file stream above seekable? True Is the file above closed? False
3. StringIO.seek(): The hľadať () funkcia sa používa na nastavenie polohy kurzora v súbore. Ak vykonáme akúkoľvek operáciu zápisu alebo čítania v dokumente, kurzor sa umiestni na index, ktorý bol naposledy použitý, aby sme ho mohli presunúť z počiatočnej pozície súboru, použije sa seek().
Syntax:
Syntax vyššie uvedenej metódy je:
File_name.seek(argument) #This argument tells the function where to place the cursor.
Príklad:
# First, we will import the StringIO module. from io import StringIO as SIO # The arbitrary string. string_1 ='Hello and thank you for visiting to Javatpoint.com.' # Here, we will use the StringIO method for setting as the file object. file_1 = SIO(string_1) # here, the user will be able to Read the file: print (file_1.read()) #If the user wishes to view the file again, it will display empty file since the #cursor has been set to the last index. It will also not print anything because #the function returns an empty string. print (file_1.read()) # So, to set the cursor position for reading or writing the file again # we can use seek() function. #We can pass any index here form(0 to len(file)) file_1.seek(0) # Now the user can read the file again print (file_1.read())S
Výkon:
Hello and thank you for visiting to Javatpoint.com. Hello and thank you for visiting to Javatpoint.com.
4. StringIO.truncate(): Táto funkcia sa používa na zmenu veľkosti toku súborov. Táto metóda uloží súbor a zahodí ho po danom indexe.
Syntax:
Syntax vyššie uvedenej metódy je:
File_name.truncate(size = None) # The user can provide the size from where to truncate the file.
Príklad:
# First, we will import the StringIO module. from io import StringIO as SIO # The arbitrary string. string_1 ='Hello and welcome to Javatpoint.com.' # Here, we will use the StringIO method for setting as the file object. file_1 = SIO(string_1) # here, we can read the initial file: print(file_1.read()) # for setting the cursor at 0. file_1.seek(0) # for dropping the file after the given index, i.e., 14. file_1.truncate(14) # here, it will print the File after truncate. print(file_1.read())
Výkon:
Hello and welcome to Javatpoint.com. Hello and welc
5. StringIO.tell(): Táto metóda sa používa na zistenie aktuálneho prúdu súboru a polohy kurzora.
Syntax:
Syntax vyššie uvedenej metódy je:
File_name.tell()
Príklad:
pole reťazcov v programovaní v c
# First, we will import the StringIO module. from io import StringIO as SIO # The arbitrary string. string_1 ='Hello and welcome to Javatpoint.com.' # Here, we will use the StringIO method for setting as the file object. file_1 = SIO(string_1) # Here the cursor is set at index '0'. print(file_1.tell()) # now, we are setting the Cursor to index '23'. file_1.seek(23) # here, we will be printing the index of cursor print(file_1.tell())
Výkon:
0 23
6. StringIO.close() Používa sa na zatvorenie súboru. Táto funkcia sa volá na súbore a nemôžeme s ním vykonávať žiadne operácie. Akákoľvek vykonaná operácia bude mať za následok a ValueError .
Syntax: =
Syntax vyššie uvedenej metódy je:
File_name.close(
Príklad:
# First, we will import the StringIO module. from io import StringIO as SIO # The arbitrary string. string_1 ='Hello and welcome to Javatpoint.com.' # Here, we will use the StringIO method for setting as the file object. file_1 = SIO(string_1) # here, we can read the initial file: print(file_1.read()) # for closing the current file. file_1.close() # If the user would perform any operation on the above file now, it will raise an #ValueError. # here, we will be using the closed function to know whether the file is closed #or not. print('Is the file closed?', file_1.closed)
Výkon:
Hello and welcome to Javatpoint.com. Is the file closed? True