strip off just newlines

[perfringo]

if i have 'foobar \t\r\n' or 'foobar \t\n\n\n' then i want to end up with 'foobar \t'.

One can chain strip operations. However, it is error prone as depends on order:

>>> first = 'foobar \t\r\n'
>>> first.rstrip('\n').rstrip('\r') 
>>> 'foobar \t'
>>> second = 'foobar \t\n\n\n' 
>>> second.rstrip('\n').rstrip('\r') 
>>> 'foobar \t'
>>> third = 'foobar' 
>>> third.rstrip('\n').rstrip('\r')    
'foobar'
>>> fourth = 'foobar \n\r'
>>> fourth.rstrip('\n').rstrip('\r') 
>>> 'foobar \n'  

But if there are only two strips needed then one can do something 'clever' like this:

>>> fourth = 'foobar \t\n\r'
>>> cutouts = ('\n', '\r') 
>>> last = fourth.endswith('\r')
>>> previous = not last
>>> fourth.rstrip(cutouts[last]).rstrip(cutouts[previous]) 
'foobar \t'
>>> fifth = 'foobar \t\r\n'
>>> last = fifth.endswith('\r')
>>> previous = not last
>>> fourth.rstrip(cutouts[last]).rstrip(cutouts[previous])
'foobar \t'

It will not help in mixed case (\r\n\r\n).

After playing with code it seems to me that str.replace is more suitable for task at hand.

[Skaperen]

i included the \t and \n in my need-example as alternate white space characters to show that i wanted splitting that includes these.