Boolean search allows you to combine keywords with operators such as AND, OR, NOT to further refine and target your search results. Wildcards are special characters that act as placeholders and can represent one or more characters in a search term. They provide more flexibility and allow you to broaden or narrow your searches in powerful ways.
What are the main wildcards used in Boolean search?
The main wildcards used in Boolean search are:
- Asterisk (*) – The asterisk represents zero, one or more characters. For example, a search for “run*” would return results for “run”, “running”, “runner” etc.
- Question mark (?) – The question mark represents any single character. For example, “run?” would return “runs”, “rung”, “runa” etc.
Some search engines may use other wildcards too like the hash/pound symbol (#) or the exclamation point (!) but the asterisk and question mark are the most common.
How does the asterisk wildcard work?
The asterisk is considered a truncation symbol that represents unknown characters. When placed at the end of a word it acts as a right-hand truncation and brings back results that contain the word stem. For example:
- “learn*” will return “learn”, “learning”, “learned” etc.
- “cat*” will return “cat”, “cats”, “category”, “cathedral” etc.
When placed at the beginning or middle of a term, the asterisk acts as a left-hand or mid-term truncation which searches for variants of the term. For example:
- “*book” will return “notebook”, “textbook”, “cookbook” etc.
- “te*t” will return “test”, “text”, “tet” etc.
The asterisk allows you to broaden a search and find all possible matches containing the word stem or a variant of the search term. It can be especially useful for plurals, different tenses of verbs, and alternate spellings.
How does the question mark wildcard work?
The question mark allows you to match any single character in place of the ? symbol. It is useful for finding variants of search terms that may have different spellings:
- “woman?” will return “woman”, “women”
- “colo?r” will return “color” and “colour”
- “anal?ze” will return “analyze” and “analyse”
You can also use multiple question marks in a search term to represent different possible characters. For example:
- “wom?n” will return “woman” and “women”
- “me??ing” will return “meeting”, “meating”, “miiting” etc.
The question mark provides more focused results than the asterisk wildcard. It looks for matches containing variants of a word with single character differences.
What are some examples of using wildcards in Boolean search?
Here are some examples of how wildcards can be used with Boolean operators like AND, OR and NOT:
- “hotel AND book*” – Finds resources related to hotels that also mention booking, bookings, booker etc.
- “hotel OR mot?l” – Returns results for hotel or motel.
- “flight NOT cancell*” – Looks for flight information excluding results about cancellations, cancelled etc.
- “econom* NOT bad” – Searches for economy or economics excluding the word bad.
- “learn* AND teach*” – Finds resources about learning and teaching.
Wildcards become even more powerful when combined with Boolean operators to zero in on precise results. You can eliminate irrelevant matches and narrow searches for maximum relevance.
What are some tips for effective use of wildcards?
Here are some useful tips for wielding wildcards effectively:
- Use truncation carefully – Broad matches could return irrelevant results. Consider alternate search terms if a wildcard returns too much.
- Avoid overusing wildcards – Too many can make your search unfocused. Use them strategically in targeted keywords.
- Experiment with wildcard placement – Moving around a wildcard can change the search’s scope.
- Combine with other limiters – Use wildcards alongside Boolean operators, filters etc. to fine-tune large result sets.
- Check which wildcards your search engine supports – Not all systems support the same wildcards.
What are the limitations of wildcards?
While wildcards open up great search flexibility, some limitations include:
- Retrieving irrelevant results – Broad matches could return unwanted variations.
- Unknown vocabulary – Words formed by wildcards may not have meaning.
- Overlooking exact matches – Variants may be prioritized over direct keyword hits.
- Unavailable in literal searches – Some search engines don’t allow wildcards in exact phrase searches.
- Complex Boolean logic – Wildcards can make queries with multiple Boolean operators complicated.
Due to these limitations, balance is key. Targeted strategic use of wildcards combined with other tools like Boolean operators and filters can overcome the downsides.
Should wildcards be avoided in advanced searches?
While wildcards can introduce limitations, they don’t necessarily need to be avoided in advanced searches. When used strategically, they can enhance precision.
Consider these advanced search examples leveraging wildcards effectively:
- “hotel NEAR booking*” – Finds hotel nearby booking offices, not just booked hotels.
- “resort AND (family OR coupl*)” – Returns resorts suitable for families or couples.
- “(COVID OR coronavirus) NOT panic” – Looks for COVID info without panic-induced results.
So advanced searches can definitely benefit from wildcards. The key is applying them selectively only where they enhance relevancy and improve result precision.
Should I use wildcards for single character or multiple character matches?
In most cases:
- Use the asterisk * for multiple characters – It allows flexible matches to word stems and variants.
- Use the question mark ? for single characters – It provides focused results with character variations.
However, the asterisk can also be used for single character matches depending on placement. For example:
- “r*n” – Will match “ran”, “run”, “rain” etc.
- “b*t” – Will match “bit”, “bat”, “bot” etc.
So the context of the search should determine if you need an asterisk or question mark wildcard for single or multiple character flexibility.
How are wildcards different from regular expressions?
Both wildcards and regular expressions (regex) allow variable matching, but there are some key differences:
Wildcards | Regular Expressions |
---|---|
– Simple syntax like * and ? | – Complex syntax and patterns |
– Match partial words | – Match entire strings/phrases |
– Limited match variations | – Powerful match capabilities |
– Easy to use | – Steep learning curve |
– Fewer features | – Advanced features like quantifiers |
So wildcards provide a more straightforward way to match character variations compared to the advanced capabilities but complexity of regex.
Should I URL encode wildcard searches?
Most search engines will automatically URL encode special characters like wildcards used in a query string. But it can be a good practice to URL encode them yourself in the search URL just to be safe.
For example, an asterisk is URL encoded as %2A. So a search URL with a wildcard would appear as:
www.searchengine.com/search?query=learn%2A
This avoids any parsing errors and ensures the wildcard is properly interpreted. URL encoding protects special characters during transmission over the web.
One exception is if a search tool allows wildcards directly in its user interface without a query URL. In that case the encoding may be handled automatically.
What are proximity searches and how do they differ from wildcards?
Proximity searches allow you to specify how closely together search terms must appear in results. For example:
- “hotel NEAR airport” – Returns results with hotel and airport within a close proximity.
- “coffee PRE/2 cream” – Finds coffee and cream within 2 words of each other.
So proximity searches look for the distance between search keywords, rather than matching on partial term variations like wildcards.
Key differences include:
Proximity Searches | Wildcards |
---|---|
Match words near each other | Match partial word variants |
Specify distance between terms | No specified distance |
Order and relationship matter | Order doesn’t matter |
Proximity and wildcards can complement each other in lookups, further refining result relevancy.
Conclusion
Wildcards are simple but extremely useful tools for Boolean search. The asterisk, question mark and other wildcards allow flexible matching of word or character variations. They help broaden or narrow searches in strategic ways to hone in on relevant results.
Mastering wildcards does take practice and experience. But combining them creatively with Boolean operators and other limiters can supercharge your search skills. A bit of experimentation will reveal just how powerful wildcards can be in tackling complex search challenges.