[Solution] Python print Statement Deprecated — Use print() Function

The print statement was the most visible change in Python 3. The statement syntax (print "hello") was replaced with a function call (print("hello")). This change unified the language syntax and made print consistent with other built-in functions. If you are migrating code from Python 2, this is almost always the first change you need to make.

What You’ll See

In Python 3, if you use the old print statement:

print "Hello, World!"

You get:

File "script.py", line 1
    print "Hello, World!"
          ^
SyntaxError: Missing parentheses in call to 'print'

If you see this error, you are running Python 2 syntax under Python 3.

Why Deprecated

The print statement was changed to a function in Python 3 for several reasons:

  • Consistency: Functions are first-class objects; a statement is not. Making print a function allowed it to be used in lambdas, map(), filter(), and as a callback.
  • Extensibility: As a function, print() accepts keyword arguments like sep, end, file, and flush, which were awkward to implement as statement modifiers.
  • Reduced syntax confusion: The statement syntax required special parsing rules (e.g., trailing comma for no newline) that were inconsistent with the rest of the language.

Old Code (Python 2 Statement)

# Simple print
print "Hello, World"

# Print with no newline (trailing comma)
print "Hello",

# Print to stderr
import sys
print >> sys.stderr, "Error occurred"

# Print multiple values
print "Name:", "Alice", "Age:", 30

# Print a variable
x = 42
print x

# Print with formatting
name = "Alice"
print "Hello, %s!" % name

New Code (Python 3 Function)

# Simple print — add parentheses
print("Hello, World")

# Print with no newline — use end keyword
print("Hello", end="")

# Print to stderr — use file keyword
import sys
print("Error occurred", file=sys.stderr)

# Print multiple values — use sep keyword
print("Name:", "Alice", "Age:", 30)
# With custom separator
print("Name:", "Alice", "Age:", 30, sep=" ")

# Print a variable
x = 42
print(x)

# Print with formatting
name = "Alice"
print(f"Hello, {name}!")  # f-string (Python 3.6+)
print("Hello, {}!".format(name))  # .format() method

Migration Using the 2to3 Tool

Python ships with an automated conversion tool called 2to3. It handles the print statement conversion and many other Python 2 to 3 changes:

# Preview changes without modifying files
2to3 -w -n script.py

# Convert an entire directory
2to3 -w -n /path/to/project/

# Preview changes only for the print fixer
2to3 -f print -w -n script.py

The -w flag writes changes to files. The -n flag skips creating backup files. Always review the diff after conversion.

Migration Using future for Python 2/3 Compatibility

If you need code that runs under both Python 2 and Python 3, use the __future__ import at the top of every file:

from __future__ import print_function

# Now this works in both Python 2 and Python 3
print("Hello, World")

# Also enables the keyword arguments
print("Hello", end=" ")
print("World")

Place the from __future__ import as the first statement in the file (after any module docstrings and comments).

Migration Steps

  1. Run 2to3 in preview mode to see all changes:
2to3 -l  # List all available fixers
2to3 -d script.py  # Show diff of proposed changes
  1. Apply the print fixer to convert all print statements:
2to3 -f print -w script.py

  1. Manually review cases where the trailing comma was used for suppressing newlines. Convert print "x", to print("x", end="").

  2. Replace % string formatting with f-strings or .format() for modern Python 3 code.

  3. Search for any remaining print statements:

grep -rn "^[[:space:]]*print " --include="*.py" /path/to/project/
  1. Run your test suite under Python 3 to verify all output is correct.