Multiple Replacements in Strings Using Dictionaries
Given a dictionary d mapping a set of keys to desired replacements and a string s containing these keys, how can you replace each occurrence of a key in s with its corresponding value from d?
Solution:
Utilizing Python's re module allows for efficient multiple replacements in strings using dictionaries:
<code class="python">import re s = 'Спорт not russianA' d = { 'Спорт': 'Досуг', 'russianA': 'englishA' } keys = (re.escape(k) for k in d.keys()) pattern = re.compile(r'\b(' + '|'.join(keys) + r')\b') result = pattern.sub(lambda x: d[x.group()], s) print(result) # Output: 'Досуг not englishA'</code>
This approach employs a regular expression pattern that matches whole words matching any of d's keys. The lambda function in the sub method performs the substitution using d.
To allow replacements within words and not only at word boundaries, modify the pattern:
<code class="python">pattern = re.compile('|'.join(re.escape(k) for k in d.keys()))</code>
In this case, sort dictionary keys descending by length to prevent matches of substrings.
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