StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>Given your rules, I'd say you really want a simple state machine. Hmm, on second thought, maybe not; you can just look back in the string as you go.</p> <p>I have a unicode string in Python and basically need to go through, character by character and replace certain ones based on a list of rules. One such rule is that a is changed to ö if a is after n. Also, if there are two vowel characters in a row, they get replaced by one vowel character and :. So if I have the string , what is the easiest and most efficient way of getting "nötaro:k"? Using Python 2.6 and CherryPy 3.1 if that matters.</p> <pre><code>vowel_set = frozenset(['a', 'e', 'i', 'o', 'u', 'ö']) def fix_the_string(s): lst = [] for i, ch in enumerate(s): if ch == 'a' and lst and lst[-1] == 'n': lst.append('ö') else if ch in vowel_set and lst and lst[-1] in vowel_set: lst[-1] = 'a' # "replaced by one vowel character", not sure what you want lst.append(':') else lst.append(ch) return "".join(lst) print fix_the_string("natarook") </code></pre> <p>EDIT: Now that I saw the answer by @Anon. I think that's the simplest approach. This might actually be faster once you get a whole bunch of rules in play, as it makes one pass over the string; but maybe not, because the regexp stuff in Python is fast C code.</p> <p>But simpler is better. Here is actual Python code for the regexp approach:</p> <pre><code>import re pat_na = re.compile(r'na') pat_double_vowel = re.compile(r'([aeiou])[aeiou]') def fix_the_string(s): s = re.sub(pat_na, r'nö', s) s = re.sub(pat_double_vowel, r'\1:', s) return s print fix_the_string("natarook") # prints "nötaro:k" </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload