n = 1
p = 4
print n += p
gives me:
File "p7.py", line 17
print n += p
SyntaxError: invalid syntax
How can this problem be fixed?
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figured it out... somewhat. taking out the print statement makes it work. I dont understand the rule here, why it breaks with print, but Ill keep looking.jason– jason2011-04-18 14:28:03 +00:00Commented Apr 18, 2011 at 14:28
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4"I dont understand the rule here"? Where have you seen code like this? What tutorial are you using? Where are you learning Python? This is example is severely wrong. Where did you see code like this?S.Lott– S.Lott2011-04-18 15:27:07 +00:00Commented Apr 18, 2011 at 15:27
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6 Answers
n += p is a statement in Python, not an expression that returns a value you could print. This is different from a couple of other languages, for example Ruby, where everything is an expression.
You need to do
n += p
print n
Comments
Assignment, including "augmented" assignment (x op= expr as shorcut for x = x op expr), is a statement, not an expression. So it doesn't result in a value. You can't print the result of something that doesn't result in anything - but that's what you're telling Python to do: "Evaluate n += p, then print the result of that."
If you want to modify n and print the new n, do that on two lines. If you just want to print the sum of n and p without modifying either, use + instead of +=.
Comments
You'll need to break it up onto separate lines:
n = 1
p = 4
n += p
print n
Comments
n += p is equal to n = n + p. This is a statement on its own and cannot be printed out. You probably meant print n + p.
EDIT:
figured it out... somewhat. taking out the print statement makes it work. I dont understand the rule here, why it breaks with print, but Ill keep looking
I would seriously suggest to get a book about Python and learn from that. You obviously (not meant as an insult, just informing you) have no idea what you are doing.
2 Comments
orlp
delnan: True, but offtopic for this problem. It would also confuse the asker, seeing his skill level approximated from the question.
+= is a statement. Place it on a line by itself.
Comments
While += is generally legal Python, it is syntactically not allowed at this point, so try:
n = 1
p = 4
n += p
print n
answered Apr 18, 2011 at 14:25
Alexander Gessler
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