[Echo]
> I have been trying to figure out the problem with this string formatting:
[monstrous statement snipped]
> when it executes, I get this error: "inv argument required".
That shoud be "int", not "inv".
> I have checked and rechecked both the string and the tuple. I cant figure
> out what the problem is. After playing around with it, i found out if change
> the last line to: "%s,%i) %(... I get a different error. The error is "not all
> arguments converted during string formatting".
>
> So I am baffled and confused as of why this wont work. Is anyone able to
> shed some light on my hidden bug?
Yup, it's precedence. Here's the same thing:
sql = "%s" + \
"%i" % ("abc", 2)
Run that and you get "int argument required". Change the last %i to
%s and you get "not all arguments converted during string formatting".
Both error messages are accurate.
That's because % binds tighter than "+". As a 1-liner, and inserting
redundant parentheses to make the precedence obvious, my simplified
example is
sql = "%s" + ("%i" % ("abc", 2))
What you intended _requires_ inserting more parentheses to force the
intended order (if you're going to stick to this confusing coding
style):
sql = ("%s" + "%i") % ("abc", 2)
Better is to not use "+" on string literals, and not use backslash
continuation either; try this instead:
sql_format = ('string1'
'string2'
'string3'
...
'last string')
Build the format in a separate statement to reduce the chance of
errors (for example, your original mistake would have been impossible
to make this way). Use parens instead of backslashes. Don't use "+"
to catenate string literals: the Python compiler automatically
catenates adjacent string literals for you, and at compile-time (so
it's even more efficient than using '"+").
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