Python Read Single Integer From File Python
Python has always remained the first choice for almost of the Information technology folks who dearest automation. With Python, y'all just demand a few lines of lawmaking to automate various It tasks, ane of those is working with files. Python tin can read files, create them, and a whole lot more.
In this tutorial, you lot will learn how to write Python lawmaking to open up, read and write to text files with tons of examples.
Permit's become started!
Prerequisites
This tutorial will exist a step-by-step tutorial. If you'd like to follow along, ensure you have the following in place:
- Python v3.6 or subsequently – This tutorial volition exist using Python v3.9.ii on a Windows 10 machine.
- A lawmaking editor – This tutorial will use Visual Studio (VS) Code.
Opening a Text File with Python
Let's get this tutorial started by first learning how to open up a file for reading in Python.
1. Open your favorite code editor; preferably one like VS Lawmaking.
ii. Create a simple text file inside the home directory (~) and proper name it every bit devops.txt with the text *"*Hi, ATA friends."
3. Now, create a file and re-create the Python code shown below to information technology and then save it equally a Python script called ata_python_read_file_demo.py in your abode directory.
# newfile is the file object , devops.txt is the file to be opened and default Access mode is read newfile = open('devops.txt') # Declaring the Access mode "read" exclusively # newfile = open up('devops.txt' , 'r') print(newfile) The higher up script contains the Python congenital-in method open() that opens the devops.txt file for reading without declaring an admission fashion. The open() method then returns a file stream which gets captured in the newfile variable.
In one case you take a file object, that object contains methods and attributes to perform various operations. When opening files, depending on what you lot intend to do with the file, yous must define a specific mode as explained above in the inline comments. At that place are diverse modes to open files in Python.
-
r– Open the file for reading. This is the default access mode. -
w– Open the file for writing. -
x– This option creates a new file if information technology no file exists only fails if already present. -
a– Opens the file for writing and appends the data at the terminate of file. -
b– Opens the file in binary mode. This fashion is used to work with files other than text such equally pdf, images, etc. -
t– Open the file in text mode. This is the default mode. -
+– Opens the file to read or write.
iv. Now, execute the Python script.
python ata_python_read_file_demo.py The output will display the file stream with details such equally type of file, access manner, and encoding.
One time you have the file open up, you can then read, write or modify information technology many different ways.
Reading a Text File with Python
Once you have a file open in Python, it's time to do something to information technology. Let'southward first encompass how to read a text file. If you lot demand to read the content inside the file, you'll need to use a Python function called read().
With the ata_python_read_file_demo.py Python script open up in your lawmaking editor from above, supersede the text with the following Python code, save and execute it.
The script below reads the entire file every bit a file stream, reads each line of the file one at a time and reads the first v characters of each line.
# Reading the file every bit one file stream file = open up('devops.txt', 'r') # Reads the entire file at once and places the contents in memory. read_content = a.read() print(read_content) # Iterating over each line in the text file with the with keyword # and reading each line one at a time with open('devops.txt', 'r') as line: # Reads a specific line of text in the file. line_text = c.readline() print(line_text) # Iterating over each line in the text file with the with keyword # and reading the first 5 characters of each line with open('devops.txt', 'r') equally line: # Reads a specific number of characters from a unmarried line of text in the file. read_char = line.read(five) print(read_char) 
Reading a CSV File with Python
You've learned that Python can open unproblematic text files. CSV files are, in actuality, just text files with a specific schema. You lot could use the open() method using the read() or readline() method to read CSV rows but information technology wouldn't be too useful. Why? Considering the read methods don't understand a CSV file's schema.
To read a CSV file so that Python understands the information the CSV stores, use the CSV Python module.
Assuming you are yet in your lawmaking editor:
1. Open some other tab and paste in the following CSV information and save it every bit ata_csv_demo.csv. Yous'll run into that this CSV information contains iv columns and iv rows.
Date, PreviousUserCount, UserCountTotal, sitepage 02-01-2021,61,5336, ATA.com/blog 03-01-2021,42,5378, ATA.com/blog1 04-01-2021,26,5404, ATA.com/blog2 05-01-2021,65,5469, ATA.com/blog3 2. Now, open another tab, create the following Python script save it every bit a Python script with a proper name of your choosing. This Python script below:
- Imports the
csvmodule to brand the methods available. - Opens the ata_csv_demo.csv file for reading.
- Reads each row in the CSV file with the
reader()method telling Python that the row is delimited with a comma. - Uses a
forloop to read the text in each row returning a Python list for each CSV tape.
# Import the CSV module import csv # Open the CSV file for reading and begin iterating over each row with open('ata_csv_demo.csv' , 'r') every bit csv_row: ## Parse the line as comma-delimited csv_data = csv.reader(csv_row, delimiter=',') # Output specific rows from csv files using the for-loop and iterates over the range() function for _ in range(5): print(next(csv_data)) print(read) In the output below, yous'll see where the script has iterated through the CSV file to show only the commencement 5 rows.
Appending to a Text File with Python
When you open a text file in Python, you aren't just relegated to reading. You can also write to text files. Let's cover in this department how to append text to an existing file.
Y'all tin can write to a text file via one of two methods:
-
write()– Writes the contents every bit a cord to the file. -
writelines()– Writes multiple strings simultaneously to the file.
At present, let's learn to append data into a text file. To do so, open another tab in your code editor, copy and paste the post-obit Python code, save it as a Python script proper name of your choosing, and execute information technology.
The beneath script is opening the devops.txt file y'all created before and appending a unmarried line to it with the write() method. It's and so using the writeLines() method to suspend multiple lines at once.
# Open the file for appending (a) and begin reading each line with open('devops.txt', 'a') as file: file.write("\nAdding 5 more than ATA friend") file.writelines(['\nAdding 5 more ATA friend', '\nAdding 15 more ATA friend']) 
Writing Data in a CSV File with Python
Past now, you have learned how to open a CSV file using Python. There are numerous times when you'll need to add data into CSV files, such every bit calculation your customer'south information, employees' salary records, employee ID, etc. Python makes your life easier writing to CSV files.
To append rows into the same file devops.csv which you created earlier, open a new lawmaking editor tab and paste the post-obit Python script into your code editor, save and execute information technology.
# importing the csv module import csv # open office within with statement Hither yous used newline since the csv module does its own (universal) newline handling. with open up('devops.csv','a', newline='') as csv_file: # open() office along with append mode "a"and newline='' write_csv = csv.writer(csv_file, delimiter=',') # csv.writer() is used to write content in the CSV file write_csv.writerow(['08-08-2021','68','8888', 'ATA.com/blog8']) # csv.writerow() to add a row and append the contentExecute the writing_into_csv.py script using Python, Open devops.csv and cheque out the last row!
Conclusion
Today you've learned how to open up, write and read different file types using Python. Using Python drastically reduces the chances of human errors compared to when you lot perform these mundane tasks manually.
Now that y'all can quickly and easily process data at speeds that you've never thought possible before, why not automate more than of your data handling tasks with Python?
Source: https://adamtheautomator.com/python-read-file/
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