ncoghlan
ncoghlan

Reputation: 41486

What does "SyntaxError: Missing parentheses in call to 'print'" mean in Python?

When I try to use a print statement in Python, it gives me this error:

>>> print "Hello, World!"
  File "<stdin>", line 1
    print "Hello, World!"
                        ^
SyntaxError: Missing parentheses in call to 'print'

What does that mean?


See Getting SyntaxError for print with keyword argument end=' ' for the opposite problem.

See Python 3 print without parenthesis for workarounds, and confirmation that print cannot be made to work like a statement in Python 3.

Upvotes: 466

Views: 1111755

Answers (11)

Alfa Bravo
Alfa Bravo

Reputation: 1991

I could also just add that I knew everything about the syntax change between Python2.7 and Python3, and my code was correctly written as print("string") and even print(f"string")...

But after some time of debugging I realized that my bash script was calling python like:

python file_name.py

which had the effect of calling my python script by default using python2.7 which gave the error. So I changed my bash script to:

python3 file_name.py

which of course uses python3 to run the script which fixed the error.

Upvotes: 5

ncoghlan
ncoghlan

Reputation: 41486

The error message SyntaxError: Missing parentheses in call to 'print' occurs when you attempt to use Python 3 syntax with the Python 2 print statement.

Example:

print "Hello, World!"

In Python 3, the print statement was replaced with a print() function, requiring parentheses around the value to be printed.

Solution

print("Hello, World!")

In Python 3, the print statement was replaced with a print() function, requiring parentheses around the value to be printed.

>>> print("Hello, World!")
Hello, World!

In earlier versions of Python 3, the interpreter just reports a generic syntax error, without providing any useful hints as to what might be going wrong:

>>> print "Hello, World!"
  File "<stdin>", line 1
    print "Hello, World!"
                        ^
SyntaxError: invalid syntax

As for why print became an ordinary function in Python 3, that didn't relate to the basic form of the statement, but rather to how you did more complicated things like printing multiple items to stderr with a trailing space rather than ending the line.

In Python 2:

>>> import sys
>>> print >> sys.stderr, 1, 2, 3,; print >> sys.stderr, 4, 5, 6
1 2 3 4 5 6

In Python 3:

>>> import sys
>>> print(1, 2, 3, file=sys.stderr, end=" "); print(4, 5, 6, file=sys.stderr)
1 2 3 4 5 6

Starting with the Python 3.6.3 release in September 2017, some error messages related to the Python 2.x print syntax have been updated to recommend their Python 3.x counterparts:

>>> print "Hello!"
  File "<stdin>", line 1
    print "Hello!"
                 ^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print("Hello!")?

Since the "Missing parentheses in call to print" case is a compile time syntax error and hence has access to the raw source code, it's able to include the full text on the rest of the line in the suggested replacement. However, it doesn't currently try to work out the appropriate quotes to place around that expression (that's not impossible, just sufficiently complicated that it hasn't been done).

The TypeError raised for the right shift operator has also been customised:

>>> print >> sys.stderr
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for >>: 'builtin_function_or_method' and '_io.TextIOWrapper'. Did you mean "print(<message>, file=<output_stream>)"?

Since this error is raised when the code runs, rather than when it is compiled, it doesn't have access to the raw source code, and hence uses meta-variables (<message> and <output_stream>) in the suggested replacement expression instead of whatever the user actually typed. Unlike the syntax error case, it's straightforward to place quotes around the Python expression in the custom right shift error message.

Upvotes: 688

Om Sao
Om Sao

Reputation: 7643

In Python 3.x, print is now a function, rather than a statement as it was in 2.x.

Therefore, print is used by calling it as a function, and thus parentheses are needed:

Python 2.x: print "Lord of the Rings"

Python 3.x: print("Lord of the Rings")

There are multiple advantages to making print a function:

  • The print function offers more flexibility when printing multiple values (which are now arguments to the function). In particular, it allows for argument splatting:
>>> items = ['foo', 'bar', 'baz']
>>> print(*items, sep='+')
foo+bar+baz
  • The behavior of calls to print can be replaced by simply writing a new function named print. This would be impossible with the print statement.

Upvotes: 15

Mr. Day
Mr. Day

Reputation: 73

print "text" is not the way of printing text in python as this won't work print("text") will print said text on your screen in the command line

Upvotes: 1

Kshitij Agarwal
Kshitij Agarwal

Reputation: 3400

So I was getting this error

from trp import BoundingBox, Document
File "C:\Users\Kshitij Agarwal\AppData\Roaming\Python\Python39\site-packages\trp\__init__.py", line 31
print ip
      ^ 
SyntaxError: Missing parentheses in call to 'print'. Did you mean print(ip)?

This is a Python package error, in which Python2 has been used and you are probably running this on Python3.

One solution could be to convert Python2 print something to Python3 print(something) for every line in each file in the package folder, which is not a good ideaπŸ˜…. I mean, you can do it but still there are better ways.

To perform the same task, there is a package named 2to3 in Python which converts Python2 scripts to Python3 scripts. To install it, execute the πŸ‘‡ command in terminal..

pip install 2to3

Then change the directory in terminal to the location where the package files are present, in my case - C:\Users\Kshitij Agarwal\AppData\Roaming\Python\Python39\site-packages\trp

Now execute the command πŸ‘‡

2to3 . -w

and voila, all the Python2 files in that directory will be converted to Python3.

Note:- The above commands hold true for other operating systems as well. Only Python package path will vary as per the system.

Upvotes: 3

CinnamonCubing
CinnamonCubing

Reputation: 381

print('Hello, World!')

You're using python 3, where you need brackets when printing.

Upvotes: 3

Sagar balai
Sagar balai

Reputation: 479

There is a change in syntax from Python 2 to Python 3. In Python 2,

print "Hello, World!" 

will work but in Python 3, use parentheses as

print("Hello, World!")

This is equivalent syntax to Scala and near to Java.

Upvotes: 26

Chad Van De Hey
Chad Van De Hey

Reputation: 2911

Outside of the direct answers here, one should note the other key difference between python 2 and 3. The official python wiki goes into almost all of the major differences and focuses on when you should use either of the versions. This blog post also does a fine job of explaining the current python universe and the somehow unsolved puzzle of moving to python 3.

As far as I can tell, you are beginning to learn the python language. You should consider the aforementioned articles before you continue down the python 3 route. Not only will you have to change some of your syntax, you will also need to think about which packages will be available to you (an advantage of python 2) and potential optimizations that could be made in your code (an advantage of python 3).

Upvotes: 2

Christian
Christian

Reputation: 26387

Unfortunately, the old xkcd comic isn't completely up to date anymore.

https://imgs.xkcd.com/comics/python.png

Since Python 3.0 you have to write:

print("Hello, World!")

And someone has still to write that antigravity library :(

Upvotes: 39

Larry
Larry

Reputation: 1322

In Python 3, you can only print as:

print("STRING")

But in Python 2, the parentheses are not necessary.

Upvotes: 6

Lukasz
Lukasz

Reputation: 267

If your code should work in both Python 2 and 3, you can achieve this by loading this at the beginning of your program:

from __future__ import print_function   # If code has to work in Python 2 and 3!

Then you can print in the Python 3 way:

print("python")

If you want to print something without creating a new line - you can do this:

for number in range(0, 10):
    print(number, end=', ')

Upvotes: 8

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