Python print statement on new line

Mastering Newlines in Python's print() Function

Explore how Python's print() function handles newlines and discover techniques to control line breaks for cleaner output.

The print() function in Python is a fundamental tool for displaying output to the console. By default, it automatically adds a newline character at the end of each statement, causing subsequent output to appear on a new line. While this behavior is often desirable, there are many scenarios where you might want to suppress this newline, add multiple newlines, or even replace the newline with a different separator. This article will guide you through the various ways to control newlines with print().

Understanding the Default Behavior

By default, the print() function in Python 3 (and Python 2's print statement) automatically appends a newline character (\n) to the end of its output. This is controlled by the end parameter, which defaults to \n.

print("Hello")
print("World")

Default print() behavior with newlines

The output of the above code will be:

Hello
World

Each print() call starts on a new line because the previous one implicitly added \n.

Suppressing the Newline Character

To prevent print() from adding a newline, you can explicitly set the end parameter to an empty string ('') or any other desired character sequence. This is particularly useful when you want to concatenate output from multiple print() statements on a single line.

print("This is on the same line", end='')
print(" as this.")

print("First part ", end='-')
print("Second part")

Using the end parameter to control newlines

The output will be:

This is on the same line as this.
First part -Second part

As you can see, setting end='' keeps the subsequent print() output on the same line, while end='-' replaces the newline with a hyphen.

Adding Multiple Newlines or Custom Separators

Beyond suppressing newlines, you can also use the end parameter to add multiple newlines or to define a custom separator between items printed within a single print() call. The sep parameter controls what is printed between multiple arguments passed to print().

print("Line 1", end='\n\n') # Adds two newlines
print("Line 2")

print("Apple", "Banana", "Cherry", sep=' | ')

Using end for multiple newlines and sep for custom separators

The output will be:

Line 1

Line 2
Apple | Banana | Cherry

This demonstrates how end='\n\n' creates an extra blank line, and sep=' | ' places a custom string between the arguments of the second print() call.

flowchart TD
    A[Start print() call]
    B{Are multiple arguments provided?}
    C[Print first argument]
    D[Print 'sep' string]
    E[Print next argument]
    F{Are there more arguments?}
    G[Print 'end' string]
    H[End print() call]

    A --> B
    B -- Yes --> C
    C --> D
    D --> E
    E --> F
    F -- Yes --> D
    F -- No --> G
    B -- No --> C
    C --> G
    G --> H

Flowchart of Python's print() function logic with sep and end

Practical Applications

Controlling newlines is crucial for formatting console output, creating progress indicators, or generating specific file formats. For instance, when building a progress bar, you might want to update the same line repeatedly.

import time

for i in range(1, 11):
    print(f"Processing item {i}/10...\r", end='')
    time.sleep(0.5)
print("Done!")

Creating a simple progress indicator using \r and end=''

In this example, \r (carriage return) moves the cursor to the beginning of the current line without advancing to the next, allowing the print() function to overwrite the previous output on the same line. Combined with end='', this creates a dynamic, single-line progress update.