Hacker News Reader

Comment by wonjohnchoi | Hacker News Reader

What is the advantage of python 2 print over python 3 print? I believe that python 3 print can do everything python 2 print can do on the same level of elegancy. Also, python 2 print has a weird trailing-comma syntax. When a trailing comma is added to a print statement, a space is printed when another print statement is used. For example,

print 'hi', # prints hi (no extra space in the end)

print 'hi',; print 'hi' # prints hi hi

I personally dislike this syntax because I don't find this natural. Wouldn't it make more sense to print an extra space after the print statement with trailing comma instead of before the next print statement?

View on HN

no trailing space is a convenient shorthand - print by itself prints with a newline (so it might make sense to have print() vs println()); print + comma omits the newline and waits for the next print statement, so that

    print 'hi',
    do_something()
    print 'there'

and

    print 'hi', 'there'

both yield

    hi there

(Assuming do_something() doesn't call print itself)

FWIW:

    pprint = functools.partial(print, end=' ')
    pprint('hi')
    do_something()
    print('there')

    print('hi', 'there', sep=' ')

I appreciate the fine grained control, and the ability to do things like `functools.partial` on it.

    fprint = functools.partial(print, file='/var/log/foo.log')
    fprint("I'm writing to a file!")
    fprint("So am I")

I understand this, but couldn't you simply wrap print itself in a function, and do that in Python 2.7 already? Granted, your method saves you one line and it's more 'natural'.

Not really, since the Python 2 version is a keyword, and not a function, you can't simply provide keyword arguments to it. You would instead have to build up a string and eval it. It would have to be something like this (completely untested):

    def print_wrapper(*args, **kwargs)
        outfile = None
        print_stmt = "print "
        if 'file' in kwargs:
            outfile = open(kwargs['file'], 'a')
            print_stmt += '>>outfile '
        print_stmt += ", ".join(*args)
        if 'end' in kwargs and kwargs['end'] == ' ':
            print_stmt += ','
        eval(print_stmt)
        if outfile is not None: outfile.close()

sep and other end values for anything other than ' ' would not be possible.

http://docs.python.org/2.6/reference/simple_stmts.html#the-p...

Reply on news.ycombinator.com