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Replace a value in a data frame based on a conditional (`if`) statement
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Short answer is:
junk$nm[junk$nm %in% "B"] <- "b"
Take a look at Index vectors in R Introduction (if you don't read it yet).
EDIT. As noticed in comments this solution works for character vectors so fail on your data.
For factor best way is to change level:
levels(junk$nm)[levels(junk...
how can I Update top 100 records in sql server
...ningless without either ORDER BY or a WHERE clause - and for both cases an index is required for large tables to be efficient.
– Simon_Weaver
Nov 5 '19 at 22:00
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Can we pass parameters to a view in SQL?
... to provide filter parameters that, for example, leverage a certain set of index(es).
– Jmoney38
Feb 22 '18 at 23:40
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Accessing MP3 metadata with Python [closed]
...he first place. Look here diveintopython.org/object%5Foriented%5Fframework/index.html
– Esteban Küber
Jan 8 '10 at 14:46
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How do I create a link using javascript?
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You paste this inside :
<A HREF = "index.html">Click here</A>
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How do you implement a “Did you mean”? [duplicate]
... is again non-trivial, your best bet is to make use of existing full text indexing and retrieval engines (i.e. not your database's one), of which Lucene is currently one of the best and coincidentally ported to many many platforms.
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How do I select an entire row which has the largest ID in the table?
...how do you expect MAX(id) to work without a full table scan? If there's no index, every value must still be checked to find the maximum.
– Michael Mior
May 4 '15 at 21:47
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Select top 10 records for each category
...to be turned into a full table sort by the query planner if there isn't an index who's first key is the RankCriteria. In this case you may get better mileage selecting the distinct sections and cross applying to pick out the top 10 ordered by RankCriteria desc.
– Joe Kearney
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Use grep --exclude/--include syntax to not grep through certain files
...ter a long time, you can add multiple includes and excludes like:
grep "z-index" . --include=*.js --exclude=*js/lib/* --exclude=*.min.js
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XMLHttpRequest Origin null is not allowed Access-Control-Allow-Origin for file:/// to file:/// (Serv
...o create a website that can be downloaded and run locally by launching its index file.
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