Supported YAML Tags¶
YAML allows defining custom so-called tags which can be distinguished during loading and serialization of objects.
paramspace
makes heavy use of this possibility, as it greatly simplifies the definition and usage of configuration files.
Python builtins and basic operators¶
paramspace.yaml
adds YAML constructors for a number of frequently used Python built-in functions and operators.
Having these available while specifying configurations can make the definition of configurations files more versatile.
Warning
The YAML tags provided here are only meant to allow basic operations, i.e. summing two parameters to create a third. Don’t overdo it. Configuration files should remain easy to read.
The tags shown below call the equivalent Python builtin or the operators defined in the operator
Python module.
Example:
any: !any [false, 0, true] # == True
all: !all [true, 5, 0] # == False
abs: !abs -1 # +1
int: !int 1.23 # 1
round: !round 9.87 # 10
sum: !sum [1, 2, 3] # 6
prod: !prod [2, 3, 4] # 24
min: !min [1, 2, 3] # 1
max: !max [1, 2, 3] # 3
sorted: !sorted [2, 1, 3] # [1, 2, 3]
isorted: !isorted [2, 1, 3] # [3, 2, 1]
# Operators
add: !add [1, 2] # 1 + 2
sub: !sub [2, 1] # 2 - 1
mul: !mul [3, 4] # 3 * 4
mod: !mod [3, 2] # 3 % 2
pow: !pow [2, 4] # 2 ** 4
truediv: !truediv [3, 2] # 3 // 2
floordiv: !floordiv [3, 2] # 3 / 2
pow_mod: !pow [2, 4, 3] # 2 ** 4 % 3
not: !not [true]
and: !and [true, false]
or: !or [true, false]
xor: !xor [true, true]
lt: !lt [1, 2] # 1 < 2
le: !le [2, 2] # 2 <= 2
eq: !eq [3, 3] # 3 == 3
ne: !ne [3, 1] # 3 != 1
ge: !ge [2, 2] # 2 >= 2
gt: !gt [4, 3] # 4 > 3
negate: !negate [1] # -1
invert: !invert [true] # ~true
contains: !contains [[1,2,3], 4] # 4 in [1,2,3] == False
concat: !concat [[1,2,3], [4,5], [6,7,8]] # […]+[…]+[…]+…
# List generation
# ... using the paramspace.tools.create_indices function
list1: !listgen [0, 10, 2] # [0, 2, 4, 6, 8]
list2: !listgen
from_range: [0, 10, 3]
unique: true
append: [100]
remove: [0]
sort: true
# ... using np.linspace, np.logspace, np.arange
lin: !linspace [-1, 1, 5] # [-1., -.5, 0., .5, 1.]
log: !logspace [1, 4, 4] # [10., 100., 1000., 10000.]
arange: !arange [0, 1, .2] # [0., .2, .4, .6, .8]
# String formatting
format1: !format ["{} is not {}", foo, bar]
format2: !format
fstr: "{some_key:}: {some_value:}"
some_key: fish
some_value: spam
format3: !format
fstr: "results: {stats[mean]:.2f} ± {stats[std]:.2f}"
stats:
mean: 1.632
std: 0.026
Recursively updating maps¶
While YAML already provides the <<
operator to update a mapping, this operator does not work recursively.
The !rec-update
YAML tag supplies exactly that functionality using the recursive_update()
function.
some_map: &some_map
foo: bar
spam: fish
some_other_map: &some_other_map
foo:
bar: baz
baz: bar
fish: spam
# Create a new map by recursively updating the first map with
# the second one (uses deep copies to avoid side effects)
merged: !rec-update [<<: *some_map, <<: *some_other_map]
# NOTE: Need to use ^^-- inheritance here, otherwise this will
# result in empty mappings (for some reason)
Warning
Always include via <<: *my_ref
!
If supplying references to mappings (as shown in the example), the references have to be included using <<: *my_ref
!
Otherwise, if using the simple *my_ref
as argument, the YAML parser does not properly resolve the reference to the anchor but only returns an empty mapping.