"TypeError: cannot concatenate 'str' and 'int' objects" when trying to use printf-style formatting
Question:
I don’t see problem in here, but Python thinks different:
x = 3
y = 7
z = 2
print "I told to the Python, that the first variable is %d!" % x
print "Anyway, 2nd and 3rd variables sum is %d. :)" % y + z
I get TypeError: cannot concatenate 'str' and 'int' objects.
Why is that so? I haven’t setted any variable as string… as much as I see.
Answers:
You need to put parenthesis: (y+z)
% has a higher precedence than +, so s % y + z is parsed as (s % y) + z.
If s is a string, then s % x is a string, and (s % y) + z attempts to add a string (the result of s % y) and an integer (the value of z).
I don’t see problem in here, but Python thinks different:
x = 3
y = 7
z = 2
print "I told to the Python, that the first variable is %d!" % x
print "Anyway, 2nd and 3rd variables sum is %d. :)" % y + z
I get TypeError: cannot concatenate 'str' and 'int' objects.
Why is that so? I haven’t setted any variable as string… as much as I see.
You need to put parenthesis: (y+z)
% has a higher precedence than +, so s % y + z is parsed as (s % y) + z.
If s is a string, then s % x is a string, and (s % y) + z attempts to add a string (the result of s % y) and an integer (the value of z).