Tai yra StringIO modulis yra atmintyje esantis į failą panašus objektas. Jis gali būti naudojamas įvesti arba išvesti daugumą funkcijų, kurių vartotojai gali tikėtis iš įprasto failo objekto. Kai vartotojas sukuria StringIO objektus, jis iš pradžių sukuriamas pateikiant eilutę konstruktoriui. Jei eilutės nėra, StringIO bus tuščias. Abiem atvejais iš pradžių rodomas žymeklis faile prasidės nuo nulio.
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Modulis nepasiekiamas naujausioje Python versijoje; Taigi, kad galėtume naudoti šį modulį, turime perkelti jį į Io modulį Python formatu io.StringIO.
Pavyzdys:
# 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())
Išvestis:
This is the initialized string. The file of the string after writing in it is: This is the initialized string. Welcome to Javatpoint.com.
Svarbūs StringIO metodai:
Toliau pateikiami keli StringIO metodai:
1. StringIO.getvalue(): Ši funkcija naudojama visam failo turiniui grąžinti.
Sintaksė:
Pirmiau pateikto metodo sintaksė yra tokia:
File_name.getvalue()
Pavyzdys:
# 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())
Išvestis:
Hello and thank you for visiting to Javatpoint.com
2. Čia apžvelgiame kai kurias StringIO funkcijas, kurios grąžina Būlio reikšmę, t. y. klaidingą arba teisingą:
Sintaksė:
Aukščiau pateikto metodo sintaksės yra šios:
1. File_name.isatty() 2. File_name.readable() 3. File_name.writable() 4. File_name.seekable() 5. File_name.closed
Pavyzdys:
# 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)
Išvestis:
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 Ieškoti() Funkcija naudojama nustatyti žymeklio vietą faile. Jei vykdome bet kokią dokumento rašymo ar skaitymo operaciją, žymeklis perkeliamas į paskutinį kartą naudotą indeksą, kad galėtume perkelti žymeklį iš pradinės failo padėties, naudojama seek().
Sintaksė:
Pirmiau pateikto metodo sintaksė yra tokia:
File_name.seek(argument) #This argument tells the function where to place the cursor.
Pavyzdys:
# 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
Išvestis:
Hello and thank you for visiting to Javatpoint.com. Hello and thank you for visiting to Javatpoint.com.
4. StringIO.truncate(): Ši funkcija naudojama failų srauto dydžiui keisti. Šis metodas išsaugo failą ir pašalina jį po nurodyto indekso.
Sintaksė:
Aukščiau pateikto metodo sintaksės yra šios:
File_name.truncate(size = None) # The user can provide the size from where to truncate the file.
Pavyzdys:
# 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())
Išvestis:
Hello and welcome to Javatpoint.com. Hello and welc
5. StringIO.tell(): Šis metodas naudojamas norint nustatyti esamą failo srautą ir žymeklio padėtį.
Sintaksė:
Aukščiau pateikto metodo sintaksės yra šios:
File_name.tell()
Pavyzdys:
# 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())
Išvestis:
0 23
6. StringIO.close() Tai naudojama failo uždarymui. Ši funkcija iškviečiama faile ir negalime su ja atlikti jokių operacijų. Bet kokia atlikta operacija sukels a ValueError .
Sintaksė: =
Aukščiau pateikto metodo sintaksės yra šios:
File_name.close(
Pavyzdys:
# 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)
Išvestis:
Hello and welcome to Javatpoint.com. Is the file closed? True