Je StringIO modul je predmet v pomnilniku, podoben datoteki. Uporablja se lahko za vnos ali izhod večine funkcij, ki jih lahko uporabniki pričakujejo od običajnega datotečnega objekta. Ko uporabnik ustvari objekte StringIO, se ti najprej ustvarijo tako, da se konstruktorju zagotovi niz. Če niza ni, bo StringIO prazen. V obeh primerih se bo prvotno prikazan kazalec na datoteki začel na nič.
Modul ni na voljo v najnovejši različici Pythona; da bi lahko uporabljali ta modul, ga moramo prenesti v modul Io v Pythonu v obliki io.StringIO.
primer:
# 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())
Izhod:
This is the initialized string. The file of the string after writing in it is: This is the initialized string. Welcome to Javatpoint.com.
Pomembne metode StringIO:
Sledi nekaj metod StringIO:
mysql seznam vseh uporabnikov
1. StringIO.getvalue(): Ta funkcija se uporablja za vrnitev celotne vsebine datoteke.
Sintaksa:
Sintaksa zgornje metode je:
File_name.getvalue()
primer:
# 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())
Izhod:
Hello and thank you for visiting to Javatpoint.com
2. Tukaj si ogledamo nekatere funkcije StringIO, ki vrnejo logično vrednost, tj. napačno ali resnično:
Sintaksa:
Sintaksa zgornje metode je:
1. File_name.isatty() 2. File_name.readable() 3. File_name.writable() 4. File_name.seekable() 5. File_name.closed
primer:
# 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)
Izhod:
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 išči() funkcija se uporablja za nastavitev položaja kazalca v datoteki. Če na dokumentu izvedemo katero koli operacijo pisanja ali branja, se kazalec postavi na indeks, ki je bil nazadnje uporabljen, tako da lahko premaknemo kazalec z začetnega položaja uporabljene datoteke seek().
niz nizov c programiranje
Sintaksa:
Sintaksa zgornje metode je:
File_name.seek(argument) #This argument tells the function where to place the cursor.
primer:
dereference kazalec
# 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
Izhod:
Hello and thank you for visiting to Javatpoint.com. Hello and thank you for visiting to Javatpoint.com.
4. StringIO.truncate(): Ta funkcija se uporablja za spreminjanje velikosti toka datoteke. Ta metoda shrani datoteko in jo spusti za podanim indeksom.
Sintaksa:
Sintaksa zgornje metode je:
File_name.truncate(size = None) # The user can provide the size from where to truncate the file.
primer:
# 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())
Izhod:
Hello and welcome to Javatpoint.com. Hello and welc
5. StringIO.tell(): Ta metoda se uporablja za sporočanje trenutnega toka datoteke in položaja kazalca.
Sintaksa:
kaj je grozdenje
Sintaksa zgornje metode je:
File_name.tell()
primer:
# 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())
Izhod:
0 23
6. StringIO.close() To se uporablja za zapiranje datoteke. Ta funkcija se kliče v datoteki in na njej ne moremo izvajati nobenih operacij. Vsaka izvedena operacija bo povzročila a ValueError .
Sintaksa: =
Sintaksa zgornje metode je:
File_name.close(
primer:
# 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)
Izhod:
Hello and welcome to Javatpoint.com. Is the file closed? True