appending two variables in os.path.isdir - python

I am trying to append two variables BUILD_ROOT_DIR and W_ROOT and check if this directory exists ,if not raise a flag...running into following syntax error while appending..what is wrong here?
if(os.path.isdir(BUILD_ROOT_DIR + W_ROOT))
raise
if(os.path.isdir(BUILD_ROOT_DIR + W_ROOT))
^
SyntaxError: invalid syntax

You need a colon to end the if statement (the parentheses are not required):
if os.path.isdir(BUILD_ROOT_DIR + W_ROOT):
raise

God gave you ':' for ending an if clause and he also told you: keep this Python tutorial under your pillow and read it all night before sleeping.
http://docs.python.org/2/tutorial/controlflow.html#if-statements

Related

What is this error message, and how do I resolve it?

I'm taking google's python tutorial and may have fat fingered a few keys, causing an error. I don't recognize the issue here, and the ctrl+click links it allows me to follow take me to line 1 of the file I'm writing in and to python.exe.
It looks like there's an extra character somewhere in a file path? There are no syntax errors in the code itself as the debugger runs through it just fine.
I'm using Visual Studio Code
None of the code I've written (with my knowledge) is causing this error.
This is the error message I'm getting.
SyntaxError: invalid syntax
>>> & C:/Users/mcgilm1/AppData/Local/Programs/Python/Python37-32/python.exe c:/Users/mcgilm1/Documents/google-python-exercises/basic/string2.py
File "<stdin>", line 1
& C:/Users/mcgilm1/AppData/Local/Programs/Python/Python37-32/python.exe c:/Users/mcgilm1/Documents/google-python-exercises/basic/string2.py
^
Including your code could help us, here is a list of things to check that I found on the web: Debugging
Make sure you are not using a Python keyword for a variable name.
Check that you have a colon at the end of the header of every compound statement, including for, while, if, and def statements.
Check that indentation is consistent. You may indent with either spaces or tabs but it’s best not to mix them. Each level should be nested the same amount.
Make sure that any strings in the code have matching quotation marks.
If you have multiline strings with triple quotes (single or double), make sure you have terminated the string properly. An unterminated string may cause an invalid token error at the end of your program, or it may treat the following part of the program as a string until it comes to the next string. In the second case, it might not produce an error message at all!
An unclosed bracket – (, {, or [ – makes Python continue with the next line as part of the current statement. Generally, an error occurs almost immediately in the next line.
Check for the classic = instead of == inside a conditional.

Getting Syntax Error in Python, but have correct number of tabs and followed syntax

In some code I just added to a larger python file that already uses the syntax of Tabs instead of spaces (which I know is not recommended), I'm getting a syntax error in the code below. I'm using vim/python2.4, and turned on :set list to see whitespace characters. It doesn't look like I'm violating any indentation rules, and I'm following what exception should look like according to the documentation/other parts of the code which are working properly.
def writeXmlFile(self, testFilekey):
#dictionary for xml values
xml_d={}
try:
xml_d['test_r']=self.test_results
except: TypeError
xml_d['test_r']=-1 <-Syntax error at the first non-whitespace (x of xml_d)
print "test_results"
print xml_d['test_r']
Does this have to do with whitespace, or is there something else that I'm overlooking completely here?
Posting code like this is not helpful; it's very hard to see the actual text.
The problem is not with indentation, but with syntax, like the error says. The colon goes after the exception class, not before:
except TypeError:
All indented blocks in Python are introduced with a colon on the end of the previous line.

Syntax error with if statement in python 2.7

I'm having trouble with a "Syntax Error: invalid syntax" message in python code that keeps moving the goals posts on me.
Here's the sample code:
another_answer = int(raw_input("> ")
if another_answer == 1:
print "The pirate's body slowly goes limp and he whispers to you......."
print "Good luck my son. You might need this."
get_gold()
print: "Do you want to continue to the next room?"
When I run this in the shell I get the following:
File "ex36.py", line 179
if another_answer == 1:
^
SyntaxError: invalid syntax
I found this bizarre, and after removing the colon I got an error message on the next line:
File "ex36.py", line 180
print "The pirate's body slowly goes limp and he slowly whispers to you......."
^
SyntaxError: invalid syntax
Similar questions I've found on stackoverflow center around improper spacing and indentation, but I've looked that over and everything seems to be well.
The preceding line is missing a closing parenthesis:
another_answer = int(raw_input("> ")
# ^ ^ ^^
# \ \--//
# \-----------?
Python allows expressions to cross physical lines when enclosed in parentheses, so when you don't close parentheses Python continues to look for the rest of the expression. By the time it reaches the : the expression makes no sense anymore and a SyntaxError exception is raised.
You're missing a closing parenthesis on the first line. The colon is simply the first character which couldn't possibly be part of an actual function argument.
You have two problems, and you have to fix both.
The first is that you're missing a closing parenthesis:
another_answer = int(raw_input("> ")
This means that Python is still trying to compile the arguments to the call to int when it gets to the next line. Until the colon, everything is still legal, because you could have been writing this:
another_answer = int(raw_input("> ")
if another_answer == 1
else '42')
But once you get to the colon, there is no valid expression that could appear in, so that's where you get the SyntaxError.
In general, when you get a SyntaxError on a line where absolutely nothing looks wrong, look to the previous line—usually it's a missing ) (or ] or }).
However, if you fix that, you're going to have another problem. Although you claim this:
Similar questions I've found on stackoverflow center around improper spacing and indentation, but I've looked that over and everything seems to be well.
… everything is definitely not well:
another_answer = int(raw_input("> ")
if another_answer == 1:
That if statement is indented to the right of that another_answer statement. That's illegal, and will raise an IndentationError. You can only change indentation levels in Python to enter or exit a block controlled by a compound statement.
You've also got at least one more error in your code:
print: "Do you want to continue to the next room?"
This will raise a SyntaxError. print isn't a compound statement like if or def, so it doesn't take a colon.
It is easy to find you missed a closing parenthesis at the first line.

Missleading Python Error Message

If I have a file python_error_msg.py
x = [e for e in range(x)
x+=1
And I run it
$ python3 python_error_msg.py
The missing bracket gives the following error:
File "python_error_msg.py", line 2
x+=1
^
SyntaxError: invalid syntax
Why does it happen this way? My error was in forgetting the ] on the list comprehension. Is this something that could be made better, or is it a deeper matter of how Python syntax works?
Also, where can I look in the
codebase
to get an idea of how error reporting works in Python?
The problem is the error isn't official until that second line. Python keeps reading while inside parentheses (or brackets, braces, etc)
What if your code were this?
x = [e for e in range(x)
]
No error.
That said, in these cases I wish SyntaxError would say:
SyntaxError: invalid syntax on line 2 of parenthetical
(After all, even the most experienced programmers forget to close parentheses sometimes

Strange error about invalid syntax

I am getting invalid syntax error in my python script for this statement
44 f = open(filename, 'r')
45 return
return
^
SyntaxError: invalid syntax
I am not sure what exactly is wrong here? I am a python newbie and so will greatly appreciate if someone can please help.
I am using version 2.3.4
I had the same problem. Here was my code:
def gccontent(genomefile):
nbases = 0
totalbases = 0
GC = 0
for line in genomefile.xreadlines():
nbases += count(seq, 'N')
totalbases += len(line)
GC += count(line, 'G' or 'C')
gcpercent = (float(GC)/(totalbases - nbases)*100
return gcpercent
'return'was invalid syntax
I simply failed to close the bracket on the following code:
gcpercent = (float(GC)/(totalbases - nbases)*100
Hope this helps.
I got an "Invalid Syntax" on return when I forgot to close the bracket on my code.
elif year1==year2 and month1 != month2:
total_days = (30-day1)+(day2)+((month2-(month1+1))*30
return (total_days)
Invalid syntax on return.
((month2-(month1+1))*30 <---- there should be another bracket
((month2-(month1+1)))*30
Now my code works.
They should improve python to tell you if you forgot to close your brackets instead of having an "invalid" syntax on return.
Getting "invalid syntax" on a plain return statement is pretty much impossible. If you use it outside of a function, you get 'return' outside function, if you have the wrong indentation you get IndentationError, etc.
The only way I can get a SyntaxError: invalid syntax on a return statement, is if in fact it doesn't say return at all, but if it contains non-ascii characters, such as retürn. That give this error. Now, how can you have that error without seeing it? Again, the only idea I can come up with is that you in fact have indentation, but that this indentation is not spaces or tabs. You can for example have somehow inserted a non-breaking space in your code.
Yes, this can happen. Yes, I have had that happen to me. Yes, you get SyntaxError: invalid syntax.
i just looked this up because i was having the same problem (invalid syntax error on plan return statement), and i am extremely new at python (first month) so i have no idea what i'm doing most of the time.
well i found my error, i had forgotten an ending parentheses on the previous line. try checking the end of the previous line for a forgotten parentheses or quote?
>>> 45 return
File "<stdin>", line 1
45 return
^
SyntaxError: invalid syntax
>>>
That might explain it. It doesn't explain the 44 f = open(filename, 'r'), but I suspect that someone copied and pasted 45 lines of code where the indentation was lost and line numbers included.
Usually it's a parenthetical syntax error. Check around the error.
I encountered a similar problem by trying to return a simple variable assignation within an "if" block.
elif len(available_spots)==0:
return score=0
That would give me a syntax error. I fixed it simply by adding a statement before the return
elif len(available_spots)==0:
score=0
return score
I had the same problem. The issue in my case was, that i mixed up datatypes in my return statement. E.g.
return string + list + string

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