如何在python 2.7中使用内联if else语句单行打印

Question

I am using python2.7. The below code works if I remove , in the print statement. but that prints the values in different lines. I want to print in same line with an inline if-statement if possible.

Here is what I have:

def binary(x):

   for i in [128,64,32,16,8,4,2,1]:
      #if x&i: print 1,
      #else: print 0,
       print 1, if x&i else 0

binary(127)

It throws the following syntax error:

File "binary.py", line 6
    print 1, if x&i else 0
              ^
SyntaxError: invalid syntax

Answer 1

def binary(x):
   for i in [128,64,32,16,8,4,2,1]:
       print 1 if x&i else 0,

binary(127)

Answer 2

Put the comma at the end :

print 1 if x&i else 0,

You are using a conditional expression, of the form true_expr if condition_expr else false_expr , and the part before the if ( true_expr ) is part of that expression. you are printing the outcome of that expression.

Answer 3

As the other answers have stated, putting the comma at the end of the print line will solve your problem.

However, there is a far easier way to achieve what you want if you use format :

>>> def binary(x):
...     return " ".join(format(n, "08b"))
...
>>> print binary(127)
0 1 1 1 1 1 1 1
>>>

This method does the same thing as your function, only it is a lot more concise and efficient.

Answer 4

x = 127

>>> [1 if ele & x else 0 for ele in [128, 64, 32, 16, 8, 4, 2, 1]]
[0, 1, 1, 1, 1, 1, 1, 1]

You can even use,

x = 127

>>> [[0,1][bool(ele & x)] for ele in [128, 64, 32, 16, 8, 4, 2, 1]]
[0, 1, 1, 1, 1, 1, 1, 1]