For questions regarding the `:=` operator available in several languages
Questions tagged [colon-equals]
60 questions
26
votes
7 answers
What is the := operator?
In some programming languages, I see (ex.):
x := y
What is this := operator generally called and what does it do?
Cole Tobin
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25
votes
2 answers
Why is := allowed as an infix operator?
I have come across the popular data.table package and one thing in particular intrigued me. It has an in-place assignment operator
:=
This is not defined in base R. In fact if you didn't load the data.table package, it would have raised an error…
xiaodai
- 14,889
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- 140
24
votes
4 answers
What is the difference between = and := in MySQL?
What is the difference in between
set test_var = 20;
and
set test_var:=20;
as they both seem to assign the value ?
hsuk
- 6,770
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- 80
19
votes
7 answers
What does := mean in Go?
I'm following this tutorial, specifically exercise 8:
http://tour.golang.org/#8
package main
import "fmt"
func swap(x, y string) (string, string) {
return y, x
}
func main() {
a, b := swap("hello", "world")
fmt.Println(a,…
sergserg
- 21,716
- 41
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- 182
17
votes
2 answers
What does := mean in vb.net?
We have this method call:
SendAck(AppData:=AppData, Status:=Status, StatusMessage:=StatusMessage, IsApplication:=IsApplication)
And here is the definition:
Private Sub SendAck(ByVal AppData As XDocument, ByVal Status As Boolean, ByVal StatusMessage…
Scott
- 2,143
- 2
- 19
- 25
16
votes
3 answers
What's the difference between :- and := in Bash parameter substitution?
What's the difference between :- and := in Bash parameter substitution?
They seem to both set the default?
Casebash
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14
votes
1 answer
colons equals operator in R? new syntax?
While reading http://ggvis.rstudio.com/interactivity.html, I noticed the code has := sprinkled in it. I assume that is a new way of providing arguments to a function? What is it exactly?
mtcars %>%
ggvis(~wt, ~mpg, size := input_slider(10,…
Chris
- 1,219
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14
votes
3 answers
What is the " := " operator in (VB).NET or what is it good for?
I see this from time to time and want to know what it is. I did try google, but its filtering out the characters from the search. I have a few books that don't reference it either.
FWIW, I remember in pascal that is was the assignment operator.…
StingyJack
- 19,041
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14
votes
2 answers
R data.table ':=' works in direct call, but same function in a package fails
Using R's data.table package,
This works:
instruction = "a = data.table(name=1:3, value=1:3, blah=1:3); a[,c('value', 'blah'):=NULL]"
eval(parse(text=instruction))
# name
#1: 1
#2: 2
#3: 3
This works:
myFunc = function(instruction)…
nsheff
- 3,063
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14
votes
3 answers
What' s the difference between <= and := in VHDL
Currently, I am learning some FPGA design techniques using VHDL, my problem is whether we can use := and <= interchangeably in VHDL or not, though I've seen the use of := in constants declarations and <= in assignments? Thanks in advance!
Jivan
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12
votes
1 answer
what does this symbol mean := in sql
What does this mean
:=
in sql ?
If found some sql using like that symbol example
select col1, col2, @pv:=col3 as 'col3' from table1
join
(select @pv:=1)tmp
where col1=@pv
ashTon
- 1,101
- 4
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- 23
12
votes
4 answers
What does ":=" mean in Pseudocode?
Really basic syntax question in pseudocode. What does := mean in Pseudocode?Example
a := 1
ElectronAnt
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10
votes
4 answers
What does a := (colon equals) in VB.NET do?
Possible Duplicate:
What is the use of the := syntax?
I've tried hunting down the MDSN documentation for := in VB.NET as well as scoured Google only to be linked to a dead MSDN page... What would the purpose of := be?
Andy Danger Gagne
- 2,107
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- 26
10
votes
1 answer
delphi object assign vs :=
Could someone explain the difference between:
(1.)
newObj := TMyObject.Create;
newObj.Assign(oldObj);
and
(2.)
newObj := oldObj;
in 2. does newObj and oldObj refer to the same single object?
Sorry if this has been covered before but is is…
Dinesh M
- 183
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- 8
10
votes
4 answers
What does operator ':=' mean?
I am trying to compile pthreads for MSVC2015 and found some strange code.
localPtr->wNodePtr->spin := PTW32_TRUE;
What is this line doing?
none7
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