Pads sequences to the same length

pad_sequences(sequences, maxlen = NULL, dtype = "int32", padding = "pre",
  truncating = "pre", value = 0)

Arguments

sequences

List of lists where each element is a sequence

maxlen

int, maximum length of all sequences

dtype

type of the output sequences

padding

'pre' or 'post', pad either before or after each sequence.

truncating

'pre' or 'post', remove values from sequences larger than maxlen either in the beginning or in the end of the sequence

value

float, padding value

Value

Matrix with dimensions (number_of_sequences, maxlen)

Details

This function transforms a list of num_samples sequences (lists of integers) into a matrix of shape (num_samples, num_timesteps). num_timesteps is either the maxlen argument if provided, or the length of the longest sequence otherwise.

Sequences that are shorter than num_timesteps are padded with value at the end.

Sequences longer than num_timesteps are truncated so that they fit the desired length. The position where padding or truncation happens is determined by the arguments padding and truncating, respectively.

Pre-padding is the default.

See also

Other text preprocessing: make_sampling_table, skipgrams, text_hashing_trick, text_one_hot, text_to_word_sequence