formap
Iterate through a map or other collection of data
formap
is a generic tool for iterating through a map, table or other sequences of data similarly like a foreach
. In fact formap
can even be used on array too.
Unlike foreach
, formap
’s default output is str
, so each new line will be treated as a list item. This behaviour will differ if any additional flags are used with foreach
, such as --jmap
.
formap
writes a list:
<stdin> -> foreach variable { code-block } -> <stdout>
formap
writes to a buffered JSON map:
<stdin> -> formap --jmap key value { code-block (map key) } { code-block (map value) } -> <stdout>
First of all lets assume the following dataset:
set json people={
"Tom": {
"Age": 32,
"Gender": "Male"
},
"Dick": {
"Age": 43,
"Gender": "Male"
},
"Sally": {
"Age": 54,
"Gender": "Female"
}
}
We can create human output from this:
» $people -> formap key value { out "$key is $value[Age] years old" }
Sally is 54 years old
Tom is 32 years old
Dick is 43 years old
Please note that maps are intentionally unsorted so you cannot guarantee the order of the output produced even if the input has been superficially set in a specific order.
With --jmap
we can turn that structure into a new structure:
» $people -> formap --jmap key value { $key } { $value[Age] }
{
"Dick": "43",
"Sally": "54",
"Tom": "32"
}
--jmap
Write a json
map to stdout instead of an arrayformap
can also work against arrays and tables as well. However foreach
is a much better tool for ordered lists and tables can look a little funky when when there are more than 2 columns. In those instances you’re better off using [
(index) to specify columns and then tabulate
for any data transformation.
Meta values are a JSON object stored as the variable $.
. The meta variable will get overwritten by any other block which invokes meta values. So if you wish to persist meta values across blocks you will need to reassign $.
, eg
%[1..3] -> foreach {
meta_parent = $.
%[7..9] -> foreach {
out "$(meta_parent.i): $.i"
}
}
The following meta values are defined:
i
: iteration number[ Index ]
: Outputs an element from an array, map or tablebreak
: Terminate execution of a block within your processes scopefor
: A more familiar iteration loop to existing developersforeach
: Iterate through an arrayjson
: JavaScript Object Notation (JSON)set
: Define a local variable and set it’s valuetabulate
: Table transformation toolswhile
: Loop until condition falseThis document was generated from builtins/core/structs/formap_doc.yaml.
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Last built on Thu Aug 15 14:38:34 UTC 2024 against commit 50ed9d650ed9d6df391240d3c2c02e623636e508dfcdad1.
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