I want to "surround" all characters in a string with pipes:

'abc'   => '|a|b|c|'
'abcde' => '|a|b|c|d|e|'
'x'     => '|x|'
''      => '|'

What's a good way to do it, preferably as a one-line expression? Here's a way with a loop:

s = 'abcde'

t = '|'
for c in s:
    t  = c   '|'

print(t)    # |a|b|c|d|e|

CodePudding user response：

Turns out we can create something from nothing:

s.replace('', '|')

Demo:

for s in 'abc', 'abcde', 'x', '':
    print(s.replace('', '|'))

Output:

|a|b|c|
|a|b|c|d|e|
|x|
|

CodePudding user response：

You can use '|'.join(), just need to add two null strings.

def f(s):
    return '|'.join(['', *s, ''])

>>> f('abc')
'|a|b|c|'
>>> f('abcde')
'|a|b|c|d|e|'
>>> f('x')
'|x|'
>>> f('')
'|'

CodePudding user response：

I recommend using string method join as follows:

''.join('|' e for e in s)   '|'

It works on all of your examples.