keras-team/keras · error · ValueError

After filtering for sequences shorter than maxlen={maxlen},

Error message

After filtering for sequences shorter than maxlen={maxlen}, no sequence was kept. Increase maxlen.

What it means

Error "After filtering for sequences shorter than maxlen={maxlen}, no sequence was kept. Increase maxlen." thrown in keras-team/keras.

Source

Thrown at keras/src/datasets/imdb.py:119

    rng.shuffle(indices)
    x_test = x_test[indices]
    labels_test = labels_test[indices]

    if start_char is not None:
        x_train = [[start_char] + [w + index_from for w in x] for x in x_train]
        x_test = [[start_char] + [w + index_from for w in x] for x in x_test]
    elif index_from:
        x_train = [[w + index_from for w in x] for x in x_train]
        x_test = [[w + index_from for w in x] for x in x_test]
    else:
        x_train = [[w for w in x] for x in x_train]
        x_test = [[w for w in x] for x in x_test]

    if maxlen:
        x_train, labels_train = remove_long_seq(maxlen, x_train, labels_train)
        x_test, labels_test = remove_long_seq(maxlen, x_test, labels_test)
        if not x_train or not x_test:
            raise ValueError(
                "After filtering for sequences shorter than maxlen="
                f"{str(maxlen)}, no sequence was kept. Increase maxlen."
            )

    xs = x_train + x_test
    labels = np.concatenate([labels_train, labels_test])

    if not num_words:
        num_words = max(max(x) for x in xs)

    # by convention, use 2 as OOV word
    # reserve 'index_from' (=3 by default) characters:
    # 0 (padding), 1 (start), 2 (OOV)
    if oov_char is not None:
        xs = [
            [w if (skip_top <= w < num_words) else oov_char for w in x]
            for x in xs
        ]

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/datasets/imdb.py:119 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/3cc8ff389f4085ec. Report an issue: GitHub.