Python - list.index

Reason is the light and the light of life.

Jerry Su Dec 03, 2020 1 mins

1. Return first index of value

Signature: text_tokens.index(value, start=0, stop=9223372036854775807, /)
Docstring:
Return first index of value.

Raises ValueError if the value is not present.
Type:      builtin_function_or_method
text_tokens = ['jerry', '<hl>', 'hello', 'world', '<hl>', 'annie']
start = text_tokens.index('<hl>')
start
1

2. Return indexes of some values

end = text_tokens.index('<hl>', start+1)
end
4

3. Example

def create_token_type_ids_from_sequences(token_ids, split_word):
    try:
        start = token_ids.index(split_word)
    except ValueError:
        return [0] * len(token_ids)
    try:
        end = token_ids.index(split_word, start + 1)
    except ValueError:
        return [0] * start + [1] * (len(token_ids) - start)
    return [0] * start + [1] * (end - start + 1) + [0] * (len(token_ids) - end -1)
text_tokens1 = ['jerry', '<hl>', 'hello', 'world', '<hl>', 'annie']
text_tokens2 = ['jerry', '<hl>', 'hello', 'world']
text_tokens3 = ['jerry', 'hello', 'world', 'annie']
create_token_type_ids_from_sequences(text_tokens1, '<hl>')
[0, 1, 1, 1, 1, 0]
create_token_type_ids_from_sequences(text_tokens2, '<hl>')
[0, 1, 1, 1]
create_token_type_ids_from_sequences(text_tokens3, '<hl>')
[0, 0, 0, 0]

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