Això és el StringIO el mòdul és un objecte en memòria, semblant a un fitxer. Es pot utilitzar per introduir o sortir la majoria de funcions que els usuaris poden esperar d'un objecte de fitxer normal. Una vegada que l'usuari crea els objectes StringIO, es crea inicialment proporcionant una cadena al constructor. Si no hi ha cap cadena, el StringIO estarà buit. En ambdós casos, el cursor que es mostra inicialment al fitxer començarà a zero.
El mòdul no està disponible a la versió més recent de Python; per tant, per poder utilitzar aquest mòdul, hem de transferir-lo al mòdul Io en Python en forma de io.StringIO.
Exemple:
linux que
# 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())
Sortida:
This is the initialized string. The file of the string after writing in it is: This is the initialized string. Welcome to Javatpoint.com.
Mètodes importants de StringIO:
A continuació es mostren alguns mètodes de StringIO:
1. StringIO.getvalue(): Aquesta funció s'utilitza per retornar tot el contingut del fitxer.
Sintaxi:
La sintaxi del mètode anterior és:
File_name.getvalue()
Exemple:
# 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())
Sortida:
Hello and thank you for visiting to Javatpoint.com
2. En això, observem algunes de les funcions de StringIO que retornen un valor booleà, és a dir, fals o vertader:
Sintaxi:
trobar a la cadena c++
Les sintaxis del mètode anterior són:
1. File_name.isatty() 2. File_name.readable() 3. File_name.writable() 4. File_name.seekable() 5. File_name.closed
Exemple:
# 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)
Sortida:
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(): El buscar() La funció s'utilitza per establir la posició del cursor dins del fitxer. Si executem qualsevol operació d'escriptura o lectura en un document, el cursor es col·loca sobre l'índex que s'ha utilitzat per darrera vegada de manera que podem moure el cursor des de la posició inicial del fitxer seek() que s'utilitza.
Sintaxi:
java conté una subcadena
La sintaxi del mètode anterior és:
File_name.seek(argument) #This argument tells the function where to place the cursor.
Exemple:
# 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
Sortida:
Hello and thank you for visiting to Javatpoint.com. Hello and thank you for visiting to Javatpoint.com.
4. StringIO.truncate(): Aquesta funció s'utilitza per canviar la mida del flux de fitxers. Aquest mètode desa el fitxer i el deixa anar després de l'índex donat.
Sintaxi:
Les sintaxis del mètode anterior són:
File_name.truncate(size = None) # The user can provide the size from where to truncate the file.
Exemple:
# 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())
Sortida:
Hello and welcome to Javatpoint.com. Hello and welc
5. StringIO.tell(): Aquest mètode s'utilitza per indicar el flux actual del fitxer i la posició del cursor.
Sintaxi:
Les sintaxis del mètode anterior són:
File_name.tell()
Exemple:
java len de matriu
# 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())
Sortida:
0 23
6. StringIO.close() S'utilitza per tancar el fitxer. Aquesta funció es crida en un fitxer i no podem fer-hi cap operació. Qualsevol operació que es faci donarà lloc a a ValueError .
Sintaxi: =
Les sintaxis del mètode anterior són:
File_name.close(
Exemple:
# 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)
Sortida:
Hello and welcome to Javatpoint.com. Is the file closed? True