In python 2.6, why is the following line valid?
my_line = 'foo' 'bar'
and if that is valid, why isn't the following:
my_list = 1 2
The first example is string concatenation, however, the following isn't valid either (thanks god):
foo = 'foo'
bar = 'bar'
foo_bar = foo bar
This is doing string literal concatenation. As noted in the documentation, advantages include the following:
This feature can be used to reduce the number of backslashes needed, to split long strings conveniently across long lines, or even to add comments to parts of strings...
It goes on to note that this concatenation is done at compilation time rather than run time.
The history and rationale behind this, and a rejected suggestion to remove the feature, is described in PEP 3126.
my_line = 'foo' 'bar' is string concatenation.
'foo' + 'bar' compiles to exactly the same bytecode, but IIRC the bytecode compiler does not always constant-fold string addition.
my_str = ('A really long string that's hard to fit on a line ' \n 'combined with another really long string on another line.') (Can't do proper formatting in comments, but imagine that spans two lines.) It's actually pretty useful and fairly common in Python source code. For what it's worth, C/C++ allow the same sort of automatic string concatenation.Perhaps this is of C's ancestry. In C, the following is perfectly valid:
char* ptr = "hello " "world";
It is implemented by the C pre-processor (cpp), and the rationale given in that link is:
this allows long strings to be split over multiple lines, and also allows string literals resulting from C preprocessor defines and macros to be appended to strings at compile time
It isn't inconsistent. Strings and integers have different methods.
Integer concatenation is meaningless.
String concatenation is a meaningful default behavior.
my_list= 1 2example seems to suggest.