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Dynamically select data frame columns using $ and a character value
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185
You can't do that kind of subsetting with $. In the source code (R/src/main/subset.c) it state...
How to show all shared libraries used by executables in Linux?
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13 Answers
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Can dplyr package be used for conditional mutating?
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Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
ifelse(a == 0 | a == 1 | a == 4 | a == 3 | c == 4, 3, NA)))
Added - if_else: Note that in dplyr 0.5 there is an if_else function defined so an alternative would be to replace ifelse with i...
How to assign from a function which returns more than one value?
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Convert RGB to RGBA over white
I have a hex color, e.g. #F4F8FB (or rgb(244, 248, 251) ) that I want converted into an as-transparent-as-possible rgba color (when displayed over white). Make sense? I'm looking for an algorithm, or at least idea of an algorithm for how to do so.
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How do I represent a hextile/hex grid in memory?
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156
Amit Patel has posted an amazing page on this topic. It's so comprehensive and wonderful that ...
How to get first character of a string in SQL?
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LEFT(colName, 1) will also do this, also. It's equivalent to SUBSTRING(colName, 1, 1).
I like LEFT, since I find it a bit cleaner, but really, there's no difference either way.
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SQL: capitalize first letter only [duplicate]
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190
Are you asking for renaming column itself or capitalise the data inside column? If its data yo...
Decreasing for loops in Python impossible?
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for n in range(6,0,-1):
print n
# prints [6, 5, 4, 3, 2, 1]
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