Something related to an assignment operation, i.e. the process of changing the content of a variable to reflect some given value.
Questions tagged [assign]
1695 questions
270
votes
16 answers
How to assign from a function which returns more than one value?
Still trying to get into the R logic... what is the "best" way to unpack (on LHS) the results from a function returning multiple values?
I can't do this apparently:
R> functionReturningTwoValues <- function() { return(c(1, 2)) }
R>…
mariotomo
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113
votes
15 answers
Assign multiple new variables on LHS in a single line
I want to assign multiple variables in a single line in R. Is it possible to do something like this?
values # initialize some vector of values
(a, b) = values[c(2,4)] # assign a and b to values at 2 and 4 indices of 'values'
Typically I want to…
user236215
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109
votes
6 answers
How to name variables on the fly?
Is it possible to create new variable names on the fly?
I'd like to read data frames from a list into new variables with numbers at the end. Something like orca1, orca2, orca3...
If I try something like
paste("orca",i,sep="")=list_name[[i]]
I get…
Maiasaura
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59
votes
4 answers
setq and defvar in Lisp
I see that the Practical Common Lisp uses (defvar *db* nil) for setting up a global variable. Isn't it OK to use setq for the same purpose?
What are the advantages/disadvantages of using defvar vs. setq?
prosseek
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48
votes
4 answers
Initializing a vector of vectors having a fixed size with boost assign
Having a vector of vector with a fixed size,
vector > v(10);
I would like to initialize it so that it has in all elements a one dimensional vector with initialized value (for example 1).
I have used Boost Assign as follows
v =…
saloua
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41
votes
3 answers
Why is using assign bad?
This post (Lazy evaluation in R – is assign affected?) covers some common ground but I am not sure it answers my question.
I stopped using assign when I discovered the apply family quite a while back, albeit, purely for reasons of elegance in…
asb
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39
votes
4 answers
R: Assign variable labels of data frame columns
I am struggling with variable labels of data.frame columns. Say I have the following data frame (part of much larger data frame):
data <- data.frame(age = c(21, 30, 25, 41, 29, 33), sex = factor(c(1, 2, 1, 2, 1, 2), labels = c("Female",…
panman
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37
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2 answers
R: what's the proper way to overwrite a function from a package?
I am using a R package, in which there are 2 functions f1 and f2 (with f2 calling f1)
I wish to overwrite function f1.
Since R 2.15 and the mandatory usage of namespace in packages, if I just source the new function, it is indeed available in the…
RockScience
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35
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4 answers
Assign multiple objects to .GlobalEnv from within a function
A post on here a day back has me wondering how to assign values to multiple objects in the global environment from within a function. This is my attempt using lapply (assign may be safer than <<- but I have never actually used it and am not…
Tyler Rinker
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31
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4 answers
In R, how to make the variables inside a function available to the lower level function inside this function?(with, attach, environment)
Update 2
@G. Grothendieck posted two approaches. The second one is changing the function environment inside a function. This solves my problem of too many coding replicates. I am not sure if this is a good method to pass through the CRAN check when…
Zhenglei
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27
votes
4 answers
How to make object created within function usable outside
I created a function which produces a matrix as a result, but I can't figure out how to make the output of this function usable outside of the function environment, so that I could for instance save it in csv file.
My code for function is the…
Sergey Samusev
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26
votes
1 answer
Why can I assign structs but not compare them
Even though I am a long time C programmer, I only recently learned that one can directly assign structure variables to one another instead of using memcpy:
struct MyStruct a,b;
...
a = b; /* implicit memcpy */
Though this feels a bit "high-level"…
Tomas
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25
votes
3 answers
`x = y, z` comma assignment in JavaScript
Possible Duplicate:
Javascript syntax: what comma means?
I came across the code while reading this article (do a Ctrl+F search for Andre Breton):
//function returning array of `umbrella` fibonacci numbers
function Colette(umbrella) {
var…
Yatharth Agarwal
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24
votes
4 answers
Assigning vs. Defining Python Magic Methods
Consider the following abhorrent class:
class MapInt:
__call__ = int
def __sub__(self, other):
return map(self, other)
__add__ = map
One can then call map(int, lst) via MapInt() - lst, i.e.
assert list(MapInt() -…
kg583
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24
votes
1 answer
Pandas how to pass DataFrame.assign arguments to add multiple new columns?
How can assign be used to return a copy of the original DataFrame with multiple new columns added?
Desired result:
df = pd.DataFrame({'A': range(1, 5), 'B': range(11, 15)})
>>> df.assign({'C': df.A.apply(lambda x: x ** 2), 'D': df.B * 2})
A B …
Alexander
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