Is there an idiom for join () with head or tail?

Question

''. join (list) is pretty big. However, I notice that I very often have to add extra characters to the beginning and end. I did this in several ways, but it seems to me that there is a more readable way that I cannot think of.

Is there an elegant way to handle it? Did I just change my mind about this?

For instance:

["column1", "column2", "column3"] 

Required Conclusion:

  | column1 | column2 | column3 | 

Code without beginning and end (short!)

 print ' | '.join(mylist) 

With head and tail:

 print ' | ' + ' | '.join(mylist) + ' | ' print ' | ', ' | '.join(mylist), ' | ' print " | {} | ".format(' | '.join(mylist)) print ' | '.join([''] + mylist + ['']) (ugh) 

Answer 1

I do not see a better way than the approaches that you have already found. Here is my preference, fixing the error when you entered extra space at the beginning and at the end:

 print ' |' + ' | '.join(list) + '| ' 

What is inconvenient for you? Is it readability? Need to repeat yourself when you create the same line in different places? If so, the answer to both of them is to pack this line as a function and use its callers.

Answer 2

I think the third option is a closet, which you can get:

 print " | {} | ".format(' | '.join(list)) 

Answer 3

Another option:

 " | " + "".join(x + " | " for x in lst) 

I don’t think there is one “good” way to do this. If you need it a lot, write a function to do what you need.

Answer 4

If you need one line:

 print "| %s |" % (' | '.join(list)) 

But probably rethinking it.

Answer 5

Adding extra blank lines at the beginning and end of the list may allow you to join without “repeating” - you can still change the delimiter by changing one character.

 " | ".join([""] + lst + [""]) 

Or avoid a temporary list if lst is large:

 from itertools import chain " | ".join(chain([""], lst, [""])