<~
Assign Or MergeMerges the right hand value to a variable on the left hand side (expression)
The Assign Or Merge operator merges your data from a the right hand side into the variable on the left hand side.
If the variable doesn’t exist, then it is created.
This operator is only available in expressions.
Lets say you have a directory hierarchy that looks like:
» tree
.
├── a
│ ├── )rPsD8Dt5EtaC4*Yyn0q
│ ├── B[E3P2@gyzl2oSfvFs5(
│ ├── WNYBb>B{Y:9oBNq~eVn{
│ ├── W~e5bLBkGkv 2sr<XTj:
│ └── lgCVRC.PkUkh(!epI(ls
├── b
│ ├── ]^[;og5$x'%Zp* TY(NR
│ ├── kKcuV<9@pBrFr@"O\j?%
│ ├── wX'\>V`4P=K}FaxE^Hra
│ ├── yXjB#Cu'{%iLtsDCkKU%
│ └── |oK7e25Dz7z&ys.?2(]E
├── c
│ ├── )Kb!TOQ]\9J6 &<Y\2qj
│ ├── -X-Dm,m[JU0FZ#b0+fe+
│ ├── Lw2"`S<ag{EnJ=YI8A\W
│ ├── W4RUF_D.z,%M|OFsLB_A
│ └── z@meR3m7h(~V4m7(V{N
├── d
│ ├── %"6Tn]&w@Uas*Gi5$?Q0
│ ├── F}Ly:]zGTk}4]V+L=Wk+
│ ├── z%;lf^2n0r'p0Fy?f[$j
│ ├── {Iz}*#HCR_@H.KyA3=xy
│ └── ~2hUs'_NftfpH`?>Bqpt
├── e
│ ├── :#'G'Rs~^~A)g,k29Er1
│ ├── =N-KR9!lh"H FjCp@sP%
│ └── ?,E XTt%TGD4vrvR@qXw
└── f
├── !B#v!iYSBmi<i6[mdlL'
├── _@$*?WgS0KozEnmHV*gW
├── eT8?OgIK@4zSHTz0$m<O
└── |c[c-8S.;X$&UzI@jp!X
7 directories, 27 files
…and in this example you want to list the files in only directories
that are vowels, you can use the Assign Or Merge
operator to append to the list on each iteration for
foreach
:
» %[a,e] -> foreach d { files <~ g($d/*) }
» $files
[
"a/)rPsD8Dt5EtaC4*Yyn0q",
"a/B[E3P2@gyzl2oSfvFs5(",
"a/WNYBb\u003eB{Y:9oBNq~eVn{",
"a/W~e5bLBkGkv 2sr\u003cXTj:",
"a/lgCVRC.PkUkh(!epI(ls",
"e/:#'G'Rs~^~A)g,k29Er1",
"e/=N-KR9!lh\"H FjCp@sP%",
"e/?,E XTt%TGD4vrvR@qXw"
]
Please note that you can also do this with standard globbing, for example:
» files = g([ae]/*)
Assign Or Merge uses the same underlying algorithm
as the alter -m
builtin.
alter
, ~>
: Change a value within a
structured data-type and pass that change along the pipeline without
altering the original source inputexpr
:
Expressions: mathematical, string comparisons, logical operatorsforeach
: Iterate through an arrayg
: Glob
pattern matching for file system objects (eg *.txt
)%[]
Array
Builder: Quickly generate arraysThis document was generated from gen/expr/assign-merge-op_doc.yaml.
This site's content is rebuilt automatically from murex's source code after each merge to the master
branch. Downloadable murex binaries are also built with the website.
Last built on Sat Aug 23 22:28:13 UTC 2025 against commit ad23f13ad23f131bfecd82ea8a12d9b3e92aab5d8398ae9.
Current version is 7.0.2129 (website) which has been verified against tests cases.