Python Readlines Without Newline

Python Readlines Without Newline are an important topic to be covered when learning the basics of Python. The readline() function is used in Python to return a single line from a file. The readlines() function is used for learning file manipulation with Python. Along with this it also returns a list containing each line in a file as an item in the list. However, at the end of each line is a trailing newline(\n), which you may want to remove to make your outputs look more comprehensive.

In this article, we will show you 4 ways to perform the Python Readlines Without Newline.

What is a newline?

The newline character is a pretty straightforward operator in Python. A newline character (\n) interpret the character as an instruction to break the line immediately, when it is introduced while executing a string. The interpreter then continues printing the string from the next line onwards. Below is a demonstration of the same

print("hello\n world")

This will give the following output –

Hello
World

Notice that the string breaks after “Hello” and then continues to print the remaining string “World” from the next line onwards.

How do you write the “Python readlines without newline” character?

Using read() and replace() method

The first method to use Python deadlines without newline characters is the read() and replace() methods. This method is used to replace newline characters with an empty string. Below is the demonstration to do the same:

First, we will be creating a file called file.txt, which we will be using for all our demonstrations.

# contents of file.txt
This is the first line.
This is the second line.
This is the third line.
This is the fourth line.

After that, create a Python file in the same directory. We will then write the following code:

with open('file.txt') as file:
    x = ' '.join(file.readlines()).replace('\n', ' ')
print(x)

Output-

This is the first line. This is the second line. This is the third line. This is the fourth line.

In this code, we used the open() method with file.txt as an argument; since we did not specify any access mode, by default, it opened in read mode and returned the file object, which we stored as x.

Then, we accessed the file object x with the read() function and read the whole text file. Then, we used the replace() method to replace newline characters, which were at the end of each line in the text file, with an empty string (‘ ‘) as seen in the code. We then passed the variable x into the print function, which was used for the output on the screen.

Using readlines(), join() & replace() method

Another method to use Python Readlines Without Newline and replace newline characters with blank spaces is the join() and replace() methods. Below is the demonstration for the same; we will use the same file.txt for the demonstration:

with open('file.txt') as file:
  x = ' '.join(file.readlines()).replace('\n', ' ')
print(x)

Output –

This is the first line. This is the second line. This is the third line. This is the fourth line.

At first glance, this code looks complicated, but it is really simple to understand. Similar to last demonstration, we will use the open() method to access the file.txt in read mode to show the Python Readlines Without Newline. Then, we will save the contents inside the file.txt object to a variable called x. After that we will use the .readlines() function to read the contents of the file object line by line and return a list of strings, and each string represents a line from file.txt. The ‘ ‘.join() is used to join the list of strings into one single string, whereas the space (‘ ‘) acts as a separator between the lines.

The replace(‘\n’, ”) removes all instances of the newline character (\n) with whitespace (‘ ‘). And then lastly, we pass the variable x into the print() function.

Using rstrip() method

The third method for Python Readlines Without Newline is to use the rstrip() method in Python. The rstrip() method is a type of string method in Python including spaces, tabs, and newline characters, used to remove trailing whitespaces at the end of lines. The term rstrip stands for “right strip”, which removes characters from the right end of the string. Below is a demonstration using the method.

x = [line.rstrip() for line in open('file.txt')]
print(x)

Output –

['This is the first line, 'This is the second line', 'This is the third line', 'This is the fourth line', 'This is the fifth line']

The open function is used to access file.txt in read mode, the default access mode. The function returns a file object. For line in open(‘file.txt’) is a list comprehension method that iterates over each line of the file object. For each new line that the list comprehension method iterates over, it updates the line variable to the value of the current line. Then the rstrip() method is used to remove trailing whitespaces, which include newline characters (\n) from the string value in the line variable. This process creates a new list, which is then passed to the x variable as a value. At the end, the print() function prints the x variable.

Using a combination of strip(), rstrip() and readlines()

The fourth and final method for Python Readlines Without Newline is a list comprehension method that integrates all three methods, strip(), rstrip(), and readlines(), into a single program to remove the trailing whitespaces from multiple lines in file.txt. Below is the demonstration for the same:

f = open('file.txt')
lines = [line.rstrip('\n') for line in f.readlines() if line.strip() != ' ']
print(lines)

Output –

['This is the first line, 'This is the second line', 'This is the third line', 'This is the fourth line,' 'This is the fifth line']

The open() function uses the file.txt as an argument. It is also used to access the file in the default read mode, the file object is then passed to the variable f. In the next line, the comprehension starts. f.readlines() reads the lines from the file and the function returns a list of strings, and each string is a line from file.txt. For lines in f.readlines(), iterates over each line in the list of strings obtained from the previous operation. The variable line takes on the value of the current line. If line.strip() != ‘ ‘ is an if condition that checks if the stripped version of the line is not equal to an empty string. If the line consists only of spaces, it is skipped. line.rstrip(‘\n’) removes the trailing newline character (‘\n’) for the right side of the current string passed to the line. The print(lines) function then prints the modified(stripped) list of lines to the console.

FAQs

Conclusion

In this article, we learned 4 methods to Python Readlines Without Newline and to remove trailing whitespaces (‘\n’) using a combination of different methods while using the readlines() method as a standard. Learning various methods for achieving the Python Readlines Without Newline is optimum for increasing your knowledge and application in areas such as file manipulation and list comprehension, and it is also extremely useful in future advanced learning. We hope we can help you remove newline characters using the readlines() method in Python with this in-depth guide. Hope this guide for Python Readlines Without Newline output will help you with all your queries.

Reference

1. readlines()
2. rstrip()

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