Create file with python and write

Create File in Python

In this tutorial, you’ll learn how to create a file in Python.

Python is widely used in data analytics and comes with some inbuilt functions to work with files. We can create a file and do different operations, such as write a file and read a file using Python.

After reading this tutorial, you’ll learn: –

• Create a file in the current directory or a specified directory
• Create a file if not exists
• Create a file with a date and time as its name
• Create a file with permissions

Table of contents

Create A Empty Text File

We don’t have to import any module to create a new file. We can create a file using the built-in function open() .

open('file_Path', 'access_mode')

Pass the file name and access mode to the open() function to create a file. Access mode specifies the purpose of opening a file.

Below is the list of access modes for creating an a file.

• The file is created in the same directory where our program/script is running.
• If you have not specified any specific path(directory location), the file is created in the working directory. It is known as creating a file using the relative path. A relative path contains the current directory and then the file name.

You can verify the result using the following four approaches

1. If the script executed without an error or exception
2. By checking the working directory manually to look for a new file
3. Use the os.listdir(directory_path) function to list all files from a folder before and after creating a file
4. Use the os.path.isfile(file_path) function to verify if a newly created file exists in a directory.

Let’s verify our operation result.

import os # list files from a working directory print(os.listdir()) # verify file exist print(os.path.isfile('sales.txt'))

['sample.txt', 'sales.txt', 'sales_2.txt'] True

Create File In A Specific Directory

To create a file inside a specific directory, we need to open a file using the absolute path. An absolute path contains the entire path to the file or directory that we need to use.

It includes the complete directory list required to locate the file. For example, /user/Pynative/data/sales.txt is an absolute path to discover the sales.txt . All of the information needed to find the file is contained in the path string.

Let’s see the example to create a file for writing using the absolute path.

# create a text file for writing with open(r'E:\pynative\reports\profit.txt', 'w') as fp: fp.write('This is first line') pass 

Note: Using the with statement a file is closed automatically it ensures that all the resources that are tied up with the file are released.

Let’s verify result using the absolute path.

import os # list files a directory print(os.listdir(r'E:\pynative\reports')) # output ['sample.txt', 'sales.txt', 'sales_2.txt' 'profit.txt'] # verify file exist print(os.path.isfile(r'E:\pynative\reports\profit.txt')) # output True

Also, you can join directory path and file name to create file at the specified location.

If you have a directory path and file name in two variables, use the os.path.join() function to construct a full path. This function accepts the directory path and file name as arguments and constructs an absolute path to create a file.

import os # Specify the directory path path = r'E:\pynative\account' file_name = 'revenue.txt' # Creating a file at specified folder # join directory and file path with open(os.path.join(path, file_name), 'w') as fp: # uncomment below line if you want to create an empty file fp.write('This is a new line')

Create a File If Not Exists

Sometimes it is essential not to create a new file if a file with the same name already exists in a given path. By default, when you open a file in write mode, it overwrites it if it exists. Else, create the new one.

We can create a file only if it is not present using the following two ways:

• Use os.path.exists(«file_path») function to check if a file exists.
• Use the access mode x in the open() function and exception handling.

Example 1: create file if not exists.

import os file_path = r'E:\pynative\account\profit.txt' if os.path.exists(file_path): print('file already exists') else: # create a file with open(file_path, 'w') as fp: # uncomment if you want empty file fp.write('This is first line')

Example 2: Use file access mode x

The access mode x open a file for exclusive creation. If the file already exists, this operation fails with FileExistsError . Use try-except block to handle this error.

try: file_path = r'E:\pynative\account\profit.txt' # create file with open(file_path, 'x') as fp: pass except: print('File already exists') 

Create File with a DateTime

Let’s see how to create a text file with the current date as its name. Use the datetime module to get the current date and time and assign it to the file name to create a file with the date and time in its name.

• Python provides a datetime module that has several classes to access and manipulate the date and timestamp value.
• First, get the current datetime value
• Next, we need to format datetime into a string to use it as a file name.
• At last, pass it to the open() function to create a file

from datetime import datetime # get current date and time x = datetime.now() # create a file with date as a name day-month-year file_name = x.strftime('%d-%m-%Y.txt') with open(file_name, 'w') as fp: print('created', file_name) # with name as day-month-year-hours-minutes-seconds file_name_2 = x.strftime('%d-%m-%Y-%H-%M-%S.txt') with open(file_name_2, 'w') as fp: print('created', file_name_2) # at specified directory file_name_3 = r"E:\demos\files_demos\account\\" + x.strftime('%d-%m-%Y-%H-%M-%S.txt') with open(file_name_3, 'w') as fp: print('created', file_name_3)

created 29-06-2021.txt created 29-06-2021-14-57-24.txt created E:\demos\files_demos\account\\29-06-2021-14-57-24.txt

Create a file with Permission

Let’s see how to create a file with permissions other users can write.

• To create a file with appropriate permissions, use os.open() to create the file descriptor and set the permission.
• Next, open the descriptor using the built-in function open()

import os file_path = r'E:\pynative\account\sample.txt' # The default umask is 0o22 which turns off write permission of group and others os.umask(0) with open(os.open(file_path, os.O_CREAT | os.O_WRONLY, 0o777), 'w') as fh: fh.write('content') 

Did you find this page helpful? Let others know about it. Sharing helps me continue to create free Python resources.

About Vishal

I’m Vishal Hule, Founder of PYnative.com. I am a Python developer, and I love to write articles to help students, developers, and learners. Follow me on Twitter

Related Tutorial Topics:

Python Exercises and Quizzes

Free coding exercises and quizzes cover Python basics, data structure, data analytics, and more.

• 15+ Topic-specific Exercises and Quizzes
• Each Exercise contains 10 questions
• Each Quiz contains 12-15 MCQ

Источник

How to write text files in Python 3?

To create text files in Python, use the open built in function with two key parameters: the file path and the mode in which the file should be opened. Use ‘w’ as the mode value to open the file for writing. Once the file is opened, call the write() build-in function and add text to the file. Here’s code that you can use to write a new text file in Python:

With open (txt_file_path, 'w') as text_file: text_file.write("Your text here")

Writing text files with Python – Detailed example

Python delivers very powerful built-in functions to create and manipulate text files. In this short tutorial we’ll go through several key capabilities:

• Create a new text file from scratch in the current folder.
• Create a new text file in a different folder.
• Add text to an existing text file.
• Writing text line by line into a file.

Let’s look into a couple of examples.

Creating a file in Python with open

To create text files in Python, we typically use a With block and the open(“filename”, “accessmode”) function. The below code will create a file named ‘mydocument.txt’ with write access permissions. This file will get created under the folder where your Python script is saved.

with open("mydocument.txt", mode = "w") as f: f.write("This text is written with Python")

Important Note: when opening a file in Write (‘w’) mode, the current file contents will be truncated. Use this mode carefully.

Create a file in a different directory path

To create a file under a path different from our working directory, we will have to make a slight change in the way we call the open function.

We will first make sure that file directory path is available in your operating system. We’ll then use a With context to open the file in Write access mode and append a string to the file. Let’s take a look at the snippet – Note the usage of the pathlib library (available from Python 3.4) that simplifies file object handling in Python.

from pathlib import Path # replace with your preferred directory path dir_path = Path('C:\Temp') file_name = "mydocument.txt" file_path = dir_path.joinpath(file_name) # check that directory exists if dir_path.is_dir(): with open(file_path, "w") as f: f.write("This text is written with Python.") print('File was created.') else: print("Directory doesn\'t exist.")

A similar implementation using the Python standard library os module (also available earlier than Python 3.4):

import os # replace with your preferred directory and file path dir_path = r"C:\Temp" file_name = "mydocument.txt" file_path = os.path.join(dir_path, file_name) # check if the directory exists if os.path.exists (dir_path): # create the file with open(file_path, "w") as f: f.write("This text is written with Python.") print('File was created.') else: print("Directory doesn\'t exist.")

Create a file if doesn’t exist with Python

Below is a bit more robust version of the code in which we’ll first check if the directory and file paths exists before reading and writing into the file.

from pathlib import Path dir_path = Path('C:\Temp') file_name = 'mydocument.txt' file_path = dir_path.joinpath(file_name) # check if directory exists if dir_path.is_dir(): # check if file already exists if file_path.is_file(): print('File already exists.') else: with open (dir_path.joinpath(file_name),'w') as f: f.write("This text is written with Python.") print('File was created.') else: print('Directory doesn\'t exist, please create the directory first.')

Append text to an existing file

As mentioned before, the files we created using “w” as access mode will overwrite all existing file contents. Hence we typically open files in append mode (“a”). Append will insert your text after the existing content of your text file. Let’s take a quick look.

#write and save with open(r"C:\Temp\mydocument.txt", "w") as f: f.write("This text is written with Python.") #read with open(r"C:\Temp\mydocument.txt", "r") as f: print("New text:\n",f.read()) #append with open(r"C:\Temp\mydocument.txt", "a") as f: f.write("\n This text was added using Append.") #read the appended text with open(r"C:\Temp\mydocument.txt", "r") as f: print("Append:\n",f.read()) 

New text: This text is written with Python. Append: This text is written with Python. This text was added using Append.

Writing a Python file line by line

Let’s now assume that you have a Python list that you would like to write into a file line by line.

The file object writelines() method expects an iterable (such as our list). However, once called writelines() will concatenate the list elements and write them into the file. If you need to write line by line, you can loop through the list elements, append the \n escape character to each element and write them into the file as shown in the snippet below:

languages = [ 'Python', 'Java', 'C#', 'Go', 'R'] file_name = 'languages.txt' #or use 'a' to append to an existing file with open (file_name, 'w') as f: for item in languages: f.write(item + '\n')

Источник