join

Concatenate a list of pools (or plain strings) end-to-end into a single composite pool. Every combination of one sequence from each input pool is produced (Cartesian product). Pass a spacer string to insert a fixed linker between adjacent segments.

import poolparty as pp
pp.init()

Parameters

Parameter	Type	Default	Description
`pools`	`list[Pool \| str]`	(required)	List of `Pool` objects or plain strings. Strings are automatically promoted to single-sequence pools.
`spacer_str`	`str`	`''`	Fixed string inserted between every adjacent pair of segments. Not itself a pool dimension.
`iter_order`	`int \| None`	`None`	Controls which pool varies fastest when enumerating combinations. The pool with the smallest value is the inner loop. Can also be set on each individual pool.
`prefix`	`str \| None`	`None`	Prefix for auto-generated sequence names.
`style`	`str \| None`	`None`	Display style applied to the joined result.

Note

Only the most commonly used parameters are shown above. For the full parameter list, see join() in the API Reference.

Examples

Join two pools (all pairwise combinations)

Joining two multi-sequence pools produces every combination of one sequence from each input.

left  = pp.from_seqs(["AA", "CC"], mode="sequential")
right = pp.from_seqs(["GG", "TT"], mode="sequential")
pool  = pp.join([left, right])
pool.print_library()

pool: seq_length=4, num_states=4 AAGG
AATT
CCGG
CCTT

Join with a fixed spacer

spacer_str inserts a constant linker between every adjacent pair.

left  = pp.from_seq("ACGT")
right = pp.from_seqs(["AAAA", "CCCC", "GGGG"], mode="sequential")
pool  = pp.join([left, right], spacer_str="TTT")
pool.print_library()

pool: seq_length=11, num_states=3 ACGTTTTAAAA
ACGTTTTCCCC
ACGTTTTGGGG

Controlling iteration order with `iter_order`

The pool with the smallest iter_order value varies fastest (inner loop). Here b is the inner loop and a is the outer loop.

a    = pp.from_seqs(["A", "C"], mode='sequential', iter_order=2)   # outer (slower)
b    = pp.from_seqs(["G", "T"], mode='sequential', iter_order=1)   # inner (faster)
pool = pp.join([a, b])
pool.print_library()

pool: seq_length=2, num_states=4 AG
AT
CG
CT

Join three pools with a literal string segment

Plain strings in the list are treated as fixed single-sequence pools, eliminating the need to call from_seq() for constant flanks.

promoter = pp.from_seqs(["AAAA", "CCCC"], mode="sequential")
insert   = pp.from_seqs(["GCGC", "TATA"], mode="sequential")
pool     = pp.join([promoter, "NNNNN", insert])
pool.print_library()

pool: seq_length=13, num_states=4 AAAANNNNNGCGC
AAAANNNNNTATA
CCCCNNNNNGCGC
CCCCNNNNNTATA

See join().