This question already has an answer here:
How does the right-shift operator work in a python print statement?
(1 answer)
Closed 6 months ago.
Looking at the source code of pstats I see this syntax:
print >> self.stream, "in %.3f seconds" % self.total_tt
print >> self.stream
What is this syntax, how is it called and how to use it? I have never seen it before, nor seen it in any of the Python books/tutorials I have read.
If you mean the >>, that's the Python 2.x syntax for writing to a file-like other than sys.stdout with print. It's defined in the Python docs, 6.6. The print statement and has been around since at least Python 2.5 (and I think earlier).
This syntax has been replaced with a file kwarg to the print function in Python 3.0.
It's the extended form of the print statement which redirects the output to the file-like object immediately following it. See the Python docs.
Related
This question already has answers here:
What is the advantage of the new print function in Python 3.x over the Python 2 print statement?
(5 answers)
Closed 4 years ago.
In Python 2.7 (interactive mode), both:
print("Hey Joe")
and:
print "Hey Joe"
give output:
"Hey Joe"
What is the difference? When should I use the former and when the latter?
Thank you
What is the difference?
Generally print 'something' is called print statement and print("something") is called print function. Print function has been introduced with Python 3. Other than that looking at the basic usage you won't notice any difference. However, you could find more here.
When should I use the former and when the latter?
If you want to make your code both Python 2.7 and Python 3 compliant than you should use print function, it is safe to import it with Python 2 and Python 3 it makes difference only with Python 2.
from __future__ import print_function
This question already has answers here:
Python 3 print without parenthesis
(10 answers)
Closed 4 years ago.
So I started learning python 3 and I wanted to run a very simple code on ubuntu:
print type("Hello World")
^
SyntaxError: invalid syntax
When I tried to compile that with command python3 hello.py in terminal it gave me the error above, but when used python hello.py (I think it means to use python 2 instead of 3) then it's all fine. Same when using python 3 and 2 shells in the terminal.
It seems like I'm missing something really stupid because I did some research and found no one with the same issue.
In Python3, print was changed from a statement to a function (with brackets):
i.e.
# In Python 2.x
print type("Hello World")
# In Python 3.x
print(type("Hello World"))
In Python 3.x print() is a function, while in 2.x it was a statement. The correct syntax in Python 3 would be:
print(type("Hello World"))
This is because from Python 3, print is a function, not a statement anymore. Therefore, Python 3 only accepts:
print(type("Hello World"))
This question already has answers here:
What's the difference between eval, exec, and compile?
(3 answers)
Closed 5 years ago.
In python, if I exec a statement which prints a value, I will see the output, e.g., exec("print 10") gives me output 10. However, if I do exec("10") I got nothing as output, where as if I type 10 in the interactive shell I got 10 as output. How do I get this output when using exec? That is if the statement to be executed is an expression, I print its result.
My question is how I can decide whether the statement to execute is an expression. Am I supposed to do the following:
def my_exec(script):
try:
print eval(compile(script, '<string>', 'eval'))
except SyntaxError:
exec(script)
# Prints 10.
my_exec("print(10)")
# Prints 10 as well.
my_exec("10")
UPDATE:
Basically I want the behavior of executing a cell in a jupyter notebook.
First of all, executing 10 doesn't make sense in real life. How can you execute a number? But, you can execute a command like exec("print(10)"). I don't see the need of creating a my_exec function. It behaves the same as the normal exec. In the interactive shell, everything works differently, so don't try to compare. Basically, exec("print(10)") is the command you are looking for. Another way not using exec is print(10).
This question already has answers here:
What does "SyntaxError: Missing parentheses in call to 'print'" mean in Python?
(11 answers)
Closed 6 years ago.
I am learning a tutorial for Python language and trying to write a basic "Hello World!" program.
But when I do all steps described in the book I receive an error.
>> print "Hello World!"
SyntaxError: Missing parentheses in call to 'print'
Why I am getting this error?
Is my book wrong?
it seems that you're using Python 3.x.
In python 3.x, the print statement is a function and you need to use it as a function like this
print("Hello World!")
Your book is right, but might be outdated a bit. It seems it describes Python version 2, but you try to run your example on the version 3.
Python 3 has changed some features and this one is the most annoying to switch from P2 to P3.
"print" statement changed to function rather than operator as was in P2.
Calling function you should always use parentheses.
So, if you want to run your program in Python3 you should call it:
print("Hello World!")
And that's it.
If you want to use examples from your book as is - install Python2 and it should work.
This question already has answers here:
Syntax error on print with Python 3 [duplicate]
(3 answers)
Closed 7 years ago.
I am a new learner to the Python language. When I want to print, I use the syntax:
print "hello world"
But when I use this syntax, it shows an error like missing parenthesis in calling print. I don't know why it is happening, because I know there is no need of using parentheses in Python to print a string like
print ("hello world")
What wrong have I done?
This is the error I get:
SyntaxError: Missing parentheses in call to 'print'
Consider:
print "hello world"
The above statement is OK when you are using Python 2.x, because in Python 2.x, print is a statement.
But in Python 3.x, print is a function and there is no way to turn it back into a statement. So you must use parentheses.
So for Python 3.x, the answer is:
print("hello world")
Please refer to: Print Is A Function.