Index
- built_in_functions
- Python abs()
- Python all()
- Python any()
- Python ascii()
- Python bin()
- Python bool()
- Python bytearray()
- Python bytes()
- Python callable()
- Python chr()
- Python classmethod()
- Python compile()
- Python complex()
- Python delattr()
- Python dict()
- Python dir()
- Python divmod()
- Python enumerate()
- Python eval()
- Python exec()
- Python filter()
- Python float()
- Python format()
- Python frozenset()
- Python getattr()
- Python globals()
- Python hasattr()
- Python hash()
- Python help()
- Python hex()
- Python id()
- Python input()
- Python int()
- Python isinstance()
- Python issubclass()
- Python iter()
- Python len()
- Python list()
- Python locals()
- Python map()
- Python max()
- Python memoryview()
- Python min()
- Python next()
- Python object()
- Python oct()
- Python open()
- Python ord()
- Python pow()
- Python print()
- Python property()
- Python range()
- Python repr()
- Python reversed()
- Python round()
- Python set()
- Python setattr()
- Python slice()
- Python sorted()
- Python staticmethod()
- Python str()
- Python sum()
- Python super()
- Python tuple() Function
- Python type()
- Python vars()
- Python zip()
- Python __import__()
- python1compute
- Python Program to Find Hash of File
- Python Program to Find the Size (Resolution) of a Image
- Python Program to Merge Mails
- Python Program to Count the Number of Each Vowel - Source Code: Using a list and a dictionary comprehension
- Python Program to Count the Number of Each Vowel - Source Code: Using Dictionary
- Python Program to Illustrate Different Set Operations
- Python Program to Sort Words in Alphabetic Order
- Python Program to Remove Punctuations From a String
- Python Program to Multiply Two Matrices - Matrix Multiplication Using Nested List Comprehension
- Python Program to Multiply Two Matrices - Source Code: Matrix Multiplication using Nested Loop
- Python Program to Transpose a Matrix - Matrix Transpose using Nested List Comprehension
- Python Program to Transpose a Matrix - Matrix Transpose using Nested Loop
- Python Program to Add Two Matrices - Source Code: Matrix Addition using Nested List Comprehension
- Python Program to Check Whether a String is Palindrome or Not
- Python Program to Add Two Matrices - Source code: Matrix Addition using Nested Loop
- Python Program to Convert Decimal to Binary Using Recursion
- Python Program to Find Factorial of Number Using Recursion
- Python Program to Find Sum of Natural Numbers Using Recursion
- Python Program to Display Fibonacci Sequence Using Recursion
- Python Program to Display Calendar
- Python Program to Shuffle Deck of Cards
- Python Program to Make a Simple Calculator
- Python Program to Find Factors of Number
- Python Program to Find LCM - Without using GCD function
- Python Program to Find HCF or GCD - Source Code: Using Euclidean Algorithm
- Python Program to Find LCM - Source Code: Using GCD function
- Python Program to Find HCF or GCD - Source Code: Using Loops
- Python Program to Find ASCII Value of Character
- Python Program to Convert Decimal to Binary, Octal and Hexadecimal
- Python Program to Find Numbers Divisible by Another Number
- Python Program To Display Powers of 2 Using Anonymous Function
- Python Program to Find the Sum of Natural Numbers
- Python Program to Find Armstrong Number in an Interval
- Python Program to Check Armstrong Number - Source Code: Check Armstrong number of n digits
- Python Program to Check Armstrong Number - Source Code: Check Armstrong number (for 3 digits)
- Python Program to Print the Fibonacci sequence
- Python Program to Display the multiplication Table
- Python Program to Find the Factorial of a Number
- Python Program to Print all Prime Numbers in an Interval
- Python Program to Find the Largest Among Three Numbers
- Python Program to Check Prime Number
- Python Program to Check Leap Year
- Python Program to Check if a Number is Odd or Even
- Python Program to Check if a Number is Positive, Negative or 0 Source Code: Using Nested if
- Python Program to Check if a Number is Positive, Negative or 0 Source Code: Using if...elif...else
- Python Program to Convert Celsius To Fahrenheit
- Python Program to Generate a Random Number
- Python Program to Convert Kilometers to Miles
- Python Program to Swap Two Variables Source Code: Without Using Temporary Variable
- Python Program to Swap Two Variables Source Code: Using temporary variable
- Python Program to Solve Quadratic Equation
- Python Program to Calculate the Area of a Triangle
- Python Program to Find the Square Root Source code: For real or complex numbers using cmath module
- Python Program to Find the Square Root Source Code: For positive numbers using exponent **
- Python Program to Add Two Numbers By One Line
- Python Program to Add Two Numbers Source Code: Add Two Numbers Provided by The User
- Python Program to Add Two Numbers
- Python Program to Print Hello world!
- python2based
Description open()
Python open()
The open() function opens the file (if possible) and returns a corresponding file object.
The syntax of open() is:
open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)
open() Parameters
• file - path-like object (representing a file system path) giving the pathname
• mode (optional) - mode while opening a file. If not provided, it defaults to
'r'
(open for reading in text mode). Available file modes are:• buffering (optional) - used for setting buffering policy
• encoding (optional) - name of the encoding to encode or decode the file
• errors (optional) - string specifying how to handle encoding/decoding errors
• newline (optional) - how newlines mode works (available values:
None
, ' '
, '\n'
, 'r'
, and '\r\n'
• closefd (optional) - must be
True
(default) if given otherwise an exception will be raised• opener (optional) - a custom opener; must return an open file descriptor
Mode | Description |
---|---|
'r' | Open a file for reading. (default) |
'w' | Open a file for writing. Creates a new file if it does not exist or truncates the file if it exists. |
'x' | Open a file for exclusive creation. If the file already exists, the operation fails. |
'a' | Open for appending at the end of the file without truncating it. Creates a new file if it does not exist. |
't' | Open in text mode. (default) |
'b' | Open in binary mode. |
'+' | Open a file for updating (reading and writing) |
Return Value from open()
The open() function returns a file object which can used to read, write and modify file.
If the file is not found, it raises
FileNotFoundError
exception.Example 1: How to open a file in Python?
---------------------------------------------------------------------------------------------------------
# opens test.text file of the current directory
f = open("test.txt")
# specifying full path
f = open("C:/Python33/README.txt")
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Since the mode is omitted, the file is opened in
'r'
mode; opens for reading.Example 2: Providing mode to open()
-------------------------------------------------------------------------------------------------------------
# opens for read
f = open("path_to_file", mode='r')
# opens for write
f = open("path_to_file", mode = 'w')
# opens for writing to the end
f = open("path_to_file", mode = 'a')
Python has a encoding system which is platform dependent.Hence, it's recommended to specify the encoding type if you are working in a text mode.f = open("path_to_file", mode = 'r', encoding='utf-8')