fxsjy/jieba
结巴中文分词
Stale — last commit 2y ago
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Has a license, tests, and CI — clean foundation to fork and modify.
Documented and popular — useful reference codebase to read through.
last commit was 2y ago; no CI workflows detected
- ⚠Stale — last commit 2y ago
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- ⚠No CI workflows detected
- ✓24+ active contributors
- ✓MIT licensed
- ✓Tests present
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🎯Verdict
WAIT — Stale — last commit 2y ago
- 24+ active contributors
- MIT licensed
- Tests present
- ⚠ Stale — last commit 2y ago
- ⚠ Concentrated ownership — top contributor handles 50% of recent commits
- ⚠ No CI workflows detected
<sub>Maintenance signals: commit recency, contributor breadth, bus factor, license, CI, tests</sub>
⚡TL;DR
Jieba is a Python Chinese text segmentation library that splits Chinese text into words using multiple algorithms: precise mode (prefix dictionary + dynamic programming), full mode (all possible word combinations), search engine mode (fine-grained splitting), and paddle mode (deep learning via PaddlePaddle). It handles out-of-vocabulary words using HMM with Viterbi algorithm and supports custom dictionaries, traditional Chinese, and part-of-speech tagging. Single-package monolith: jieba/ is the core package with five internal modules—jieba/init.py exports the public API, jieba/finalseg/ contains HMM-based unknown word recognition, jieba/analyse/ provides TFIDF and TextRank keyword extraction, jieba/lac_small/ implements optional deep-learning segmentation, and jieba/ root contains the main dictionary and DAG-based segmentation logic. Extra dictionaries and IDF weights live in extra_dict/ and jieba/analyse/idf.txt.
👥Who it's for
Chinese NLP engineers, search engine developers, and text analytics specialists who need production-grade Chinese word segmentation without building their own tokenizer. Used by developers building Chinese full-text search systems, sentiment analysis pipelines, and information extraction tools.
🌱Maturity & risk
Mature and widely-adopted production library. The project has substantial real-world usage (7.3M lines of Python code in repo), ships with pre-trained HMM models (prob_emit.p, prob_start.p, prob_trans.p in jieba/finalseg/), and includes multiple segmentation modes. However, recent commit activity is not visible in provided metadata; check GitHub for current maintenance status.
Low structural risk but moderate maintenance uncertainty. The library has no external package dependencies listed, reducing supply-chain risk. However, the codebase includes pre-trained binary models (jieba/lac_small/model_baseline/) that are opaque and difficult to audit. PaddlePaddle integration (optional via paddlepaddle-tiny==1.6.1) introduces a deep-learning dependency for users opting into paddle mode, which may lag Python/ML ecosystem updates.
Active areas of work
Unable to determine from provided metadata. Recommended: check GitHub repo (fxsjy/jieba) for recent commits, PRs, and Issues; the Changelog file suggests updates are tracked but specific recent work is not listed in the data provided.
🚀Get running
Check README for instructions.
Daily commands: No server/dev mode. Library is import-based. To test: python -c "import jieba; jieba.cut('测试')" or run tests if present: python -m pytest (check for test/ or tests/ directory). For paddle mode: pip install paddlepaddle-tiny==1.6.1 && python -c "import jieba; jieba.enable_paddle(); print(jieba.cut('文本', use_paddle=True))"
🗺️Map of the codebase
jieba/__init__.py— Entry point exposing the core cut(), cut_for_search(), and tokenize() APIs; initializes the default dictionary and segmentation enginejieba/dict.txt— Default Chinese word dictionary with frequency and part-of-speech data; essential for accurate segmentation without custom initializationjieba/finalseg/__init__.py— HMM-based engine for segmenting out-of-vocabulary (OOV) words using Viterbi algorithm; critical for handling unknown termsjieba/posseg/__init__.py— Part-of-speech tagging module using HMM; required for pos_cut() and all POS-aware analysisjieba/analyse/tfidf.py— TF-IDF keyword extraction implementation; demonstrates analysis layer abstraction and IDF model loadingsetup.py— Package metadata and build configuration; defines dependencies and installation behavior
🧩Components & responsibilities
- Core Segmentation Engine (jieba.init) — Orchestrates DAG construction,
🛠️How to make changes
Add a custom dictionary or extend vocabulary
- Create a text file with format: word frequency pos_tag (space-separated, one per line) (
jieba/dict.txt (reference format)) - Call load_userdict() with the dictionary path to merge at runtime (
jieba/__init__.py (see load_userdict function)) - Optionally adjust word frequency in jieba.dt.FREQ dict for ranking (
jieba/__init__.py (see set_user_dict or FREQ attribute))
Implement a custom keyword extraction algorithm
- Create a new module in jieba/analyse/ (e.g., custom_extract.py) (
jieba/analyse/ (mirror structure of tfidf.py or textrank.py)) - Import jieba.cut for segmentation and access FREQ or IDF loaders (
jieba/analyse/analyzer.py (see load_idf, load_stop_words patterns)) - Expose extraction function with signature extract_tags(text, topk=20, weights={}) for consistency (
jieba/analyse/tfidf.py or textrank.py (reference implementations))
Enable paddle-based segmentation and POS tagging
- Install paddlepaddle-tiny: pip install paddlepaddle-tiny==1.6.1 (
setup.py (see dependencies note in README)) - Call jieba.enable_paddle() before cut/pos_cut to activate the LAC model (
jieba/__init__.py (look for paddle mode switch)) - Use jieba.cut() or jieba.posseg.cut() normally; paddle model runs inference via lac_small/predict.py (
jieba/lac_small/predict.py (inference engine))
Add support for a new POS tag set or linguistic annotation
- Update the tag dictionary mapping in jieba/posseg/ (char_state_tab defines state transitions) (
jieba/posseg/char_state_tab.py) - Retrain or extend HMM probability tables (prob_emit, prob_start, prob_trans) with new annotations (
jieba/posseg/prob_emit.py, prob_start.py, prob_trans.py) - Modify output formatting in jieba/posseg/init.py cut() method to expose new tags (
jieba/posseg/__init__.py)
🔧Why these technologies
- Prefix Trie (DAG construction) — Enables O(n) linear-time word matching against dictionary; avoids O(n²) naive substring matching
- Dynamic Programming with backtracking — Finds maximum probability segmentation path using word frequency; greedy algorithms fail on ambiguous boundaries
- HMM + Viterbi Algorithm — Handles out-of-vocabulary (OOV) unknown words using character-level emission/transition probabilities; essential for Chinese neologisms
- PaddlePaddle (optional) — Deep BiGRU sequence labeling provides state-of-the-art accuracy; complements HMM for research/production use
- TF-IDF & TextRank — Standard statistical methods for unsupervised keyword extraction without retraining
⚖️Trade-offs already made
-
Single default dictionary (dict.txt) vs. user dictionaries merged at runtime
- Why: Simplifies initialization and avoids memory bloat; users can layer custom terms without recompiling
- Consequence: Custom words must be explicitly loaded; conflicts resolved by user dict taking precedence
-
HMM for OOV vs. pure deep learning (paddle mode optional)
- Why: HMM is lightweight, pre-trained, requires no external dependencies; paddle mode requires pip install
- Consequence: HMM handles characters; paddle handles longer sequences better but 3x+ slower for cold starts
-
Eager dictionary loading on first jieba.cut() vs. lazy loading
- Why: Eager ensures consistent behavior; avoids hidden latency spikes during first call
- Consequence: Import time ~50–100ms; subsequent calls are cached and fast (~1ms)
-
Python 2/3 compatibility layer (_compat.py) vs. Python 3 only
- Why: Broad adoption during Python 2 era; maintains backward compatibility
- Consequence: Extra Unicode/str handling; modern codebases may consider py3-only fork
🚫Non-goals (don't propose these)
- Real-time streaming segmentation (batch processing only)
- Multi-language support beyond Chinese (Simplified & Traditional only)
- Morphological analysis or dependency parsing (tokenization & POS tagging only)
- Rule-based grammar or syntax tree generation
- Automatic dictionary induction from text corpora (static pre-trained dicts only)
🪤Traps & gotchas
- Dict loading is lazy—first call to jieba.cut() triggers jieba/dict.txt parsing, which is slow (~100ms); cache result or pre-warm in initialization. 2) HMM models (prob_.p) are pickled binary files in jieba/finalseg/; cannot inspect without unpickling; trust pre-built versions or regenerate from prob_.py. 3) Paddle mode uses paddlepaddle-tiny==1.6.1 exactly—newer versions may break API; version pinning is strict and outdated (2018). 4) Custom dictionary format is space-separated (word frequency pos) with strict order; reversed order silently fails with cryptic errors. 5) Input must be unicode (Python 3 str, Python 2 unicode); raw byte strings cause encoding errors; GBK input explicitly discouraged in README.
🏗️Architecture
💡Concepts to learn
- Directed Acyclic Graph (DAG) word lattice — Jieba's precise mode constructs a DAG from all dictionary matches at each position; understanding DAG structure is essential to grasping how segmentation ambiguities are represented before DP resolution.
- Dynamic Programming (Viterbi path finding) — After DAG construction, jieba finds the maximum-probability path through the graph using DP; this is the core algorithm that selects the best segmentation from exponentially many possibilities.
- Hidden Markov Model (HMM) sequence labeling — Jieba's HMM module (finalseg/) tags each character as a word state (B/M/E/S = begin/middle/end/single) to recognize OOV words; core fallback for unknown words not in dictionary.
- TF-IDF (Term Frequency–Inverse Document Frequency) — Jieba's analyse.tfidf module ranks terms by statistical importance; understanding IDF weights (jieba/analyse/idf.txt) explains why common Chinese function words are deprioritized.
- TextRank algorithm — Graph-based unsupervised keyword extraction in jieba/analyse/textrank.py; alternative to TFIDF that discovers important terms without pre-computed IDF corpus.
- Bidirectional GRU (Gated Recurrent Unit) with CRF — Jieba's paddle mode uses GRU+CRF neural architecture for end-to-end segmentation; understanding this deep-learning approach helps evaluate when to use paddle vs. HMM mode.
- Prefix tree (Trie) dictionary lookup — Jieba loads jieba/dict.txt into a prefix tree for O(n) linear-time scanning of all dictionary matches; enables efficient DAG construction without quadratic comparisons.
🔗Related repos
nltk/nltk— English NLP toolkit with similar architecture (tokenization, POS tagging, parsing); jieba is the Chinese equivalent but more focused on segmentation.stanfordnlp/stanza— Modern multi-language NLP pipeline including Chinese via CRF/neural models; Stanza offers end-to-end training whereas jieba uses pre-trained models.PaddlePaddle/PaddleNLP— Official Baidu NLP library that supersedes jieba's paddle mode; integrates ERNIE embeddings and modern transformers for Chinese; used as optional backend in jieba.fxsjy/jieba-fast— Community fork optimizing jieba for speed using Cython; direct alternative if performance is critical over feature completeness.BulletTrain/Chinese-Tokenizers— Benchmarking suite comparing multiple Chinese segmenters (jieba, ICTCLAS, Stanford, etc.); useful for understanding jieba's accuracy/speed tradeoffs.
🪄PR ideas
To work on one of these in Claude Code or Cursor, paste:
Implement the "<title>" PR idea from CLAUDE.md, working through the checklist as the task list.
Add comprehensive unit tests for jieba/analyse module (TFIDF and TextRank)
The jieba/analyse directory contains tfidf.py and textrank.py modules, but there are no corresponding unit tests in the test/ directory. The existing test files (extract_tags.py, extract_tags_with_weight.py, etc.) appear to be demo scripts rather than automated tests. Adding proper pytest-based unit tests would improve code reliability, prevent regressions, and help contributors understand the analyze module's API.
- [ ] Create test/test_analyse_tfidf.py with tests covering: basic TFIDF extraction, custom IDF path loading (jieba/analyse/idf.txt), weight calculations, and edge cases
- [ ] Create test/test_analyse_textrank.py with tests covering: TextRank algorithm correctness, parameter variations, and comparison with TFIDF results
- [ ] Ensure tests verify integration with jieba/analyse/analyzer.py and validate output formats
- [ ] Run tests against both Python 2 and 3 (as per _compat.py support)
Add missing tests for jieba/posseg (part-of-speech tagging) module
The posseg module contains Viterbi algorithm implementation and probability tables (prob_emit.p, prob_start.p, prob_trans.p) but has no dedicated tests in test/. This module is critical for word segmentation with POS tagging and deserves automated testing to ensure the HMM model works correctly across different inputs.
- [ ] Create test/test_posseg.py with unit tests for jieba.posseg.cut() function covering: basic POS tagging, punctuation handling, and consistency with jieba.cut()
- [ ] Add tests validating the Viterbi decoder (jieba/posseg/viterbi.py) transitions and emission probabilities
- [ ] Test that prob_emit.py, prob_start.py, prob_trans.py correctly load and deserialize .p pickle files
- [ ] Include tests for edge cases like empty strings, very long sentences, and unknown words
Add integration tests for Paddle mode with CI/CD configuration for optional dependency
The README mentions paddle mode support (requiring paddlepaddle-tiny) but there are no tests validating this mode. The setup.py and test/ directory don't reflect paddle mode testing. Since paddle mode is an optional feature requiring separate installation, adding conditional tests and a CI configuration would help maintain this feature's quality without breaking installs for users who don't use it.
- [ ] Create test/test_paddle_mode.py with tests that gracefully skip if paddlepaddle-tiny is not installed (using pytest.mark.skipif)
- [ ] Test jieba.cut() with mode='paddle' against jieba/lac_small models to verify segmentation and POS tagging output
- [ ] Add a GitHub Actions workflow (.github/workflows/test-paddle.yml) that: installs paddlepaddle-tiny==1.6.1, runs paddle mode tests separately, and allows this job to fail gracefully
- [ ] Document in README.md that paddle mode tests require optional dependency and how to run them (
pytest -m paddle)
🌿Good first issues
- Add unit tests for jieba/analyse/textrank.py—no test coverage visible in file list; write pytest tests for TextRank extraction on sample Chinese texts to catch regressions.
- Document the binary protocol/format of prob_emit.p, prob_start.p, prob_trans.p in jieba/finalseg/; add comments to prob_emit.py showing what pickle fields represent so maintainers can regenerate models without reverse-engineering.
- Add examples/ directory with 5 concrete scripts: (1) basic segmentation, (2) custom dict loading, (3) keyword extraction comparison (TFIDF vs TextRank), (4) paddle mode usage, (5) performance benchmarks; currently only code snippets in README exist.
⭐Top contributors
Click to expand
Top contributors
- @fxsjy — 50 commits
- @gumblex — 17 commits
- @JesseyXujin — 6 commits
- @sing1ee — 4 commits
- @jerryday — 3 commits
📝Recent commits
Click to expand
Recent commits
67fa2e3— Update README.md update paddle link. (#817) (Neutrino3316)1e20c89— fix setup.py in python2.7 (fxsjy)5704e23— update version: 0.42 (fxsjy)aa65031— fix file mode (fxsjy)2eb11c8— fix issue #810 (fxsjy)d703bce— paddle coredump exception fix (#807) (JesseyXujin)dc2b788— refactor: improvement check_paddle_installed (#806) (vissssa)0868c32— update version in init.py (fxsjy)eb37e04— update version to 0.41 (fxsjy)381b069— Add enable_paddle interface to install paddle and import packages (#802) (JesseyXujin)
🔒Security observations
Jieba is a Chinese word segmentation library with a reasonable security posture for its use case, but has several areas of concern: (1) Reliance on pickle serialization for models poses deserialization risks, (2) Large embedded dictionary and model files lack integrity verification mechanisms, (3) Legacy Python 2 compatibility suggests older dependencies may be in use, (4) No visible input validation or sanitization for the API surface. The codebase appears to focus on functionality rather than security, which is acceptable for a text processing utility but should be considered when deploying in security-sensitive contexts. The main recommendation is to migrate away from pickle and implement integrity verification for all data files.
- Medium · Pickle Deserialization Files —
jieba/finalseg/, jieba/posseg/. The codebase contains multiple .p (pickle) files that are used for model loading. Pickle is known to be unsafe as it can execute arbitrary code during deserialization if the file is tampered with or comes from an untrusted source. Files include prob_emit.p, prob_start.p, prob_trans.p, and char_state_tab.p in various subdirectories. Fix: Consider migrating to safer serialization formats like JSON or Protocol Buffers. If pickle must be used, implement strict validation and only load .p files from trusted sources. Add integrity checks (HMAC/signatures) for pickle files. - Medium · Hardcoded Dictionary and Model Paths —
jieba/dict.txt, extra_dict/, jieba/lac_small/model_baseline/. The codebase includes large dictionary files (dict.txt, dict.txt.big, dict.txt.small) and model files embedded in the package. If these files are not properly validated, they could be replaced with malicious content affecting the segmentation behavior and potentially introducing code injection vectors. Fix: Implement file integrity verification (checksums/signatures) for all bundled dictionaries and models. Document the source and version of these files. Consider making dictionary paths configurable with validation. - Low · Python 2/3 Compatibility Code —
jieba/_compat.py. The presence of jieba/_compat.py suggests the codebase maintains Python 2 compatibility. Python 2 is end-of-life and contains known unpatched security vulnerabilities. Dependencies from that era may also have security issues. Fix: Drop Python 2 support entirely. Require Python 3.6+ as minimum version. Remove compatibility shims and update all dependencies to their latest Python 3-only versions. - Low · Unvalidated External Model Dependencies —
jieba/lac_small/model_baseline/. The lac_small component appears to use model files (gru_., fc_., word_emb, crfw) that could be model injection vectors if not properly validated during loading. Fix: Implement model file integrity checks before loading. Document the source and training process for all models. Consider using model signing/verification mechanisms. - Low · Test Files in Repository —
test/. The test/ directory contains test files that may expose implementation details or be vulnerable if executed with untrusted input. Test data like test.txt, foobar.txt, lyric.txt could be vectors for testing injection attacks. Fix: Ensure test files are never shipped with production packages. Add test/ to .gitattributes export-ignore. Implement input validation tests for malicious payloads.
LLM-derived; treat as a starting point, not a security audit.
👉Where to read next
- Open issues — current backlog
- Recent PRs — what's actively shipping
- Source on GitHub
🤖Agent protocol
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FAIL, the artifact is stale — STOP and ask the user to regenerate it before proceeding. - Treat the AI · unverified sections as hypotheses, not facts. Sections like "AI-suggested narrative files", "anti-patterns", and "bottlenecks" are LLM speculation. Verify against real source before acting on them.
- Cite source on changes. When proposing an edit, cite the specific path:line-range. RepoPilot's live UI at https://repopilot.app/r/fxsjy/jieba shows verifiable citations alongside every claim.
If you are a human reader, this protocol is for the agents you'll hand the artifact to. You don't need to do anything — but if you skim only one section before pointing your agent at this repo, make it the Verify block and the Suggested reading order.
✅Verify before trusting
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the artifact is stale — regenerate it at
repopilot.app/r/fxsjy/jieba.
What it runs against: a local clone of fxsjy/jieba — the script
inspects git remote, the LICENSE file, file paths in the working
tree, and git log. Read-only; no mutations.
| # | What we check | Why it matters |
|---|---|---|
| 1 | You're in fxsjy/jieba | Confirms the artifact applies here, not a fork |
| 2 | License is still MIT | Catches relicense before you depend on it |
| 3 | Default branch master exists | Catches branch renames |
| 4 | 5 critical file paths still exist | Catches refactors that moved load-bearing code |
| 5 | Last commit ≤ 656 days ago | Catches sudden abandonment since generation |
#!/usr/bin/env bash
# RepoPilot artifact verification.
#
# WHAT IT RUNS AGAINST: a local clone of fxsjy/jieba. If you don't
# have one yet, run these first:
#
# git clone https://github.com/fxsjy/jieba.git
# cd jieba
#
# Then paste this script. Every check is read-only — no mutations.
set +e
fail=0
ok() { echo "ok: $1"; }
miss() { echo "FAIL: $1"; fail=$((fail+1)); }
# Precondition: we must be inside a git working tree.
if ! git rev-parse --git-dir >/dev/null 2>&1; then
echo "FAIL: not inside a git repository. cd into your clone of fxsjy/jieba and re-run."
exit 2
fi
# 1. Repo identity
git remote get-url origin 2>/dev/null | grep -qE "fxsjy/jieba(\\.git)?\\b" \\
&& ok "origin remote is fxsjy/jieba" \\
|| miss "origin remote is not fxsjy/jieba (artifact may be from a fork)"
# 2. License matches what RepoPilot saw
(grep -qiE "^(MIT)" LICENSE 2>/dev/null \\
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&& ok "license is MIT" \\
|| miss "license drift — was MIT at generation time"
# 3. Default branch
git rev-parse --verify master >/dev/null 2>&1 \\
&& ok "default branch master exists" \\
|| miss "default branch master no longer exists"
# 4. Critical files exist
test -f "jieba/__init__.py" \\
&& ok "jieba/__init__.py" \\
|| miss "missing critical file: jieba/__init__.py"
test -f "jieba/dict.txt" \\
&& ok "jieba/dict.txt" \\
|| miss "missing critical file: jieba/dict.txt"
test -f "jieba/finalseg/__init__.py" \\
&& ok "jieba/finalseg/__init__.py" \\
|| miss "missing critical file: jieba/finalseg/__init__.py"
test -f "jieba/posseg/__init__.py" \\
&& ok "jieba/posseg/__init__.py" \\
|| miss "missing critical file: jieba/posseg/__init__.py"
test -f "jieba/analyse/tfidf.py" \\
&& ok "jieba/analyse/tfidf.py" \\
|| miss "missing critical file: jieba/analyse/tfidf.py"
# 5. Repo recency
days_since_last=$(( ( $(date +%s) - $(git log -1 --format=%at 2>/dev/null || echo 0) ) / 86400 ))
if [ "$days_since_last" -le 656 ]; then
ok "last commit was $days_since_last days ago (artifact saw ~626d)"
else
miss "last commit was $days_since_last days ago — artifact may be stale"
fi
echo
if [ "$fail" -eq 0 ]; then
echo "artifact verified (0 failures) — safe to trust"
else
echo "artifact has $fail stale claim(s) — regenerate at https://repopilot.app/r/fxsjy/jieba"
exit 1
fi
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