Python缩进

Question

I thought every line in pythton is a statment, but have a look below:

class Report(p.Report):
 def create(self):
   self.set(background=sp.LightYellow)
   self.add(p.Row(p.Text("Trip Name",
                  valign=p.CENTER,
                  font=p.font(weight=p.BOLD)),
            p.Column(p.Text("Costs",
                     align=p.CENTER)))

I thought we are not allowed to get to next line unless the statement is ended. It writes valign = p.CENTER in the next line. How is it possible? How can we break a line and continue the statement in the next line? It has also written p.Column in another line, but it has the same indent with p.Row, is it a rule?

Answer 1

Put simply, a statement can continue on to the next line as long as there is an open parenthesis or bracket or brace.

Valid:

print ("hello " 
        "world"
        "!")

Invalid:

print "hello " 
       "world"
       "!"

Answer 2

The second you open a bracket (either round or square) all identation is ignored until you close that one:

print(1,
           15,
  4)

is perfectly equal to

print(1, 15, 4)

Answer 3

The line isn't closed until all the () are matched. Also works for [] and {}

Answer 4

No, statements can continue across in several cases. In this case, the presence of an open parentheses for an argument list means that the statement doesn't end until the parentheses closes. The same is true for brackets and parens marking the beginning and end of lists, tuples, dicts.

Answer 5

No, it's allowed to write a statement on 2 line if there's the bracket wrapping. For example we can write:

a = ('1' + '2' + '3' +
    '4' + '5')