The challenge
Write your own implementation of the built-in split function in Python.
The following rules must be adhered to:
- the function cannot use, in any way, the original
splitorrsplitfunctions, - the new function must be a generator,
- it should behave as the built-in
split, so it will be tested that way — think ofsplit()andsplit('')
The solution in Python
Option 1:
import re
def my_very_own_split(string, delimiter = None):
if delimiter == '': raise ValueError('empty delimiter')
if delimiter == None: delimiter = '\s+'
else: delimiter = re.escape(delimiter)
pos = 0
for m in re.finditer(delimiter, string):
yield string[pos:m.start()]
pos = m.end()
yield string[pos:]
Option 2:
import re
def my_very_own_split(s, dell = None):
f = []
if dell=='': raise SyntaxError
if dell:
while dell in s:
f.append(s[:s.find(dell)])
s = s[s.find(dell)+len(dell):]
return f+[s]
return re.split(r'[\s]*',s)
Option 3:
from string import whitespace, maketrans
convert_whitespace = lambda s: s.translate(maketrans(whitespace, ' ' * len(whitespace)))
def my_very_own_split(strng, sep=None):
start, fil = 0, False
if sep == '': raise ValueError("empty separator")
if sep is None: sep, fil, strng = ' ', True, convert_whitespace(strng)
while start <= len(strng):
end = strng.find(sep, start)
if end < 0: end = len(strng)
if not fil or strng[start: end]: yield strng[start: end]
start = end + len(sep)
Test cases to validate our solution
s, d = 'abc,def,ghi', ','
test.assert_equals(list(my_very_own_split(s, d)), ['abc', 'def', 'ghi'])
s, d = 'This is a test', ' '
test.assert_equals(list(my_very_own_split(s, d)), ['This', 'is', 'a', 'test'])
s, d = 'This is a test', ','
test.assert_equals(list(my_very_own_split(s, d)), ['This is a test'])
