Description
Choose a uniform exact-size deletion index subset, retaining source positions and one-is-deleted mask; does not edit payload data.
A random construction is defined by its sampling support: positions, permutations, complete tilings, proposal sequences or another explicit set. Uniform choices at one stage do not necessarily make final visible outcomes uniform. A replay seed gives a deterministic sequence; equal values can hide different sampled positions. These tools are for reproducible synthetic examples rather than cryptographic entropy.
Choose a uniform exact-size deletion index subset, retaining source positions and one-is-deleted mask; does not edit payload data.
When to use this tool
Use this tool to choose a uniform exact-size deletion index subset, retaining source positions and one-is-deleted mask; does not edit payload data.
How to use the tool and how it works
- Enter length, deletions, seed using the definitions below.
- Run the operation. Resolve input-format errors before interpreting an output.
- Read result.seed, result.deleted, result.mask, using the stated boundary, ordering, sign and absence conventions.
Choose deletions distinct positions uniformly within length, sort them and return both those indexes and a numeric 0/1 mask where one marks deletion.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| length | Explicit integer source/sequence length under the bounds stated above. | Finite safe integer satisfying the stated bounds. |
| deletions | Integer deletion count from 1 through length. | Finite safe integer satisfying the stated bounds. |
| seed | Nonblank replay seed, at most 256 UTF-16 code units; an injected source overrides seeded draws. | Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply. |
| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.seed | Original supplied seed string; injected-source replay additionally requires that source’s state. |
| result.deleted | Sorted distinct original deletion indexes. |
| result.mask | Numeric 0/1 deletion mask in original position order; one means deleted. |
{
"input": {
"length": 5,
"deletions": 2,
"seed": "batch56"
},
"output": {
"result": {
"seed": "batch56",
"deleted": [
3,
4
],
"mask": [
0,
0,
0,
1,
1
]
}
}
}Limitations and assumptions
- length is 1–128 and deletions 1–length. This selects positions without deleting values from an external sequence.
- A nonblank seed of at most 256 UTF-16 code units is required. With ordinary use the seed initializes one deterministic advancing source; an application-injected random source takes precedence and the seed alone then cannot replay the result. Uniformity statements assume independent uniform source draws in [0,1). Source calls are bounded and degenerate injected sources can fail a rejection budget. This is not cryptographically secure.
- Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
- Ordinary numeric outputs must be finite and within safe-integer magnitude. Exact large lengths/counts use decimal strings. Original record indexes and code-unit positions are zero-based; span ends are exclusive unless stated otherwise.
Alternative or Complementary methods
Choose a generator whose support matches the intended experiment and retain source-position provenance. Use a separate statistically justified process model or cryptographic source where those properties matter.
References
Similar or alternative tools
- Random One-Hot Index Mask
Choose one uniform left-to-right bit index and return its one-hot text mask; no integer endianness inference.
- Random Contiguous Bit Burst Mask
Choose one uniform nonwrapping contiguous positive bit burst start; the mask is left-to-right text, not an encoded integer.