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Difference between Math.Floor() and Math.Truncate()
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12 Answers
12
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Is there a better way of writing v = (v == 0 ? 1 : 0); [closed]
I want to toggle a variable between 0 and 1. If it's 0 I want to set it to 1, else if it's 1 I want to set it to 0.
31 Answ...
How to select rows from a DataFrame based on column values?
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10 Answers
10
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What does ** (double star/asterisk) and * (star/asterisk) do for parameters?
...a tuple:
def foo(*args):
for a in args:
print(a)
foo(1)
# 1
foo(1,2,3)
# 1
# 2
# 3
The **kwargs will give you all
keyword arguments except for those corresponding to a formal parameter as a dictionary.
def bar(**kwargs):
for a in kwargs:
print(a, kwargs[a])
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How do you detect where two line segments intersect? [closed]
...first line segment (p + t r):
t0 = (q − p) · r / (r · r)
t1 = (q + s − p) · r / (r · r) = t0 + s · r / (r · r)
If the interval between t0 and t1 intersects the interval [0, 1] then the line segments are collinear and overlapping; otherwise they are collinear and disj...
Convert column classes in data.table
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105
For a single column:
dtnew <- dt[, Quarter:=as.character(Quarter)]
str(dtnew)
Classes ‘...
Code Golf: Collatz Conjecture
Inspired by http://xkcd.com/710/ here is a code golf for it.
70 Answers
70
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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 update gradle in android studio?
I installed Android Studio 0.1.9. Today I got and update to version 0.2 and of course I updated. After the installation I restarted Android Studio but now I get this message:
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