flip

Produce forward and reverse-complement variants of a pool as distinct states. Unlike rc() (which always reverses), flip tracks orientation as part of the pool’s state dimension: sequential mode enumerates both orientations deterministically; random mode coin-flips each draw with a configurable probability.

import poolparty as pp
pp.init()

Parameters

Parameter	Type	Default	Description
`pool`	`Pool \| str`	(required)	The background Pool or sequence string. Must be a DNA pool.
`region`	`str \| list \| None`	`None`	Region to flip. A named tag (str), `[start, stop]` interval, or `None` to flip the full sequence.
`rc_prob`	`float`	`0.5`	Probability of reverse complement in random mode. Ignored in sequential mode.
`prefix`	`str \| None`	`None`	Prefix for auto-generated sequence names.
`mode`	`str`	`'sequential'`	`'sequential'` enumerates forward then RC as two states; `'random'` coin-flips per draw using `rc_prob`.
`num_states`	`int \| None`	`None`	Override the natural state count. In sequential mode the natural count is 2 (cycling if greater). In random mode, `None` means one draw per call.
`iter_order`	`int \| None`	`None`	Enumeration order when combined with other pools.
`style`	`str \| None`	`None`	Display style applied to the reverse-complemented variant only.
`cards`	`list \| dict \| None`	`None`	Design card keys to include. Available key: `'flip'` (value: `'forward'` or `'rc'`).

Note

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

Examples

Sequential mode — both orientations

mode='sequential' produces two states: forward then RC.

wt      = pp.from_seq("ATCGATCG")
flipped = wt.flip(mode="sequential", style="red")
flipped.print_library()

flipped: seq_length=8, num_states=2 ATCGATCG
CGATCGAT

Random mode with custom rc_prob

mode='random' samples orientation per draw. Here rc_prob=0.3 means 30% chance of RC on each draw.

wt      = pp.from_seq("ATCGATCG")
flipped = wt.flip(mode="random", rc_prob=0.3, num_states=5, style="red")
flipped.print_library()

flipped: seq_length=8, num_states=5 ATCGATCG
ATCGATCG
ATCGATCG
ATCGATCG
CGATCGAT

Flip only a named region

region restricts the RC operation to a tagged segment; flanks are returned unchanged.

wt      = pp.from_seq("AAAA<cre>ATCGATCG</cre>TTTT")
flipped = wt.flip(region="cre", style="red")
flipped.print_library()

flipped: seq_length=16, num_states=2 AAAA<cre>ATCGATCG</cre>TTTT
AAAA<cre>CGATCGAT</cre>TTTT

Flip a multi-state pool

Flipping a pool with multiple states doubles the library: each variant appears once in the forward orientation and once reverse-complemented.

variants = pp.from_seqs(["AACG", "TTAG", "GCCA"], mode="sequential")
both     = variants.flip(style="red")
both.print_library()

both: seq_length=4, num_states=6 AACG
CGTT
TTAG
CTAA
GCCA
TGGC

See flip().