大约有 48,000 项符合查询结果（耗时：0.0670秒） [XML]
Can dplyr package be used for conditional mutating?
...
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...
Logical operators for boolean indexing in Pandas
...
219
When you say
(a['x']==1) and (a['y']==10)
You are implicitly asking Python to convert (a['x'...
Most popular screen sizes/resolutions on Android phones [closed]
...
61
You can see the resolutions for those categories in the Table 2, in this section: http://develop...
Convert column classes in data.table
...
105
For a single column:
dtnew <- dt[, Quarter:=as.character(Quarter)]
str(dtnew)
Classes ‘...
Print all but the first three columns
...
19 Answers
19
Active
...
Using numpy to build an array of all combinations of two arrays
...
10 Answers
10
Active
...
Difference between '..' (double-dot) and '…' (triple-dot) in range generation?
...
158
The documentation for Range† says this:
Ranges constructed using .. run from the beginni...
How to return a part of an array in Ruby?
...
195
Yes, Ruby has very similar array-slicing syntax to Python. Here is the ri documentation for th...
Is there an equivalent for the Zip function in Clojure Core or Contrib?
...
(map vector '(1 2 3) '(4 5 6))
does what you want:
=> ([1 4] [2 5] [3 6])
Haskell needs a collection of zipWith (zipWith3, zipWith4, ...) functions, because they all need to be of a specific type; in particular, the number of input...