Add StringArray::num_chars for calculating number of characters
#1503
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Signed-off-by: remzi <13716567376yh@gmail.com>
| /// This function has `O(n)` time complexity where `n` is the string length. | ||
| /// If you can make sure that all chars in the string are in the range `U+0x0000` ~ `U+0x007F`, | ||
| /// please use the function [`value_length`](#method.value_length) which has O(1) time complexity. | ||
| pub fn num_chars(&self, i: usize) -> usize { |
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I don't find an elegant way to make the returned type as OffsetSize.
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I think returning the length as a usize is a good API and is what would be expected by rust programmers 👍
| /// # Performance | ||
| /// This function has `O(n)` time complexity where `n` is the string length. | ||
| /// If you can make sure that all chars in the string are in the range `U+0x0000` ~ `U+0x007F`, | ||
| /// please use the function [`value_length`](#method.value_length) which has O(1) time complexity. |
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length of string == number of chars when all chars are in 0000 ~ 007F
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I wonder if you have considered using array.value(i).chars().len() to count utf8 codepoints, as described in
https://stackoverflow.com/questions/46290655/get-the-string-length-in-characters-in-rust?
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I wonder if you have considered using
array.value(i).chars().len()to count utf8 codepoints, as described in https://stackoverflow.com/questions/46290655/get-the-string-length-in-characters-in-rust?
Thank you for your helpful suggestion, I will have a try!
update doc and test Signed-off-by: remzi <13716567376yh@gmail.com>
Codecov Report
@@ Coverage Diff @@
## master #1503 +/- ##
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+ Coverage 82.70% 82.73% +0.03%
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Files 188 188
Lines 54403 54359 -44
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- Hits 44993 44974 -19
+ Misses 9410 9385 -25
Continue to review full report at Codecov.
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| @@ -377,9 +386,9 @@ mod tests { | |||
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| #[test] | |||
| fn test_string_array_from_u8_slice() { | |||
| let values: Vec<&str> = vec!["hello", "", "parquet"]; | |||
| let values: Vec<&str> = vec!["hello", "", "A£ऀ𖼚𝌆৩ƐZ"]; | |||
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Thanks @HaoYang670 and @liukun4515 for the review |
alamb
changed the title
StringArrayStringArray::num_chars for calculating number of characters
Which issue does this PR close?
Closes #1493 .
Rationale for this change
We need a method to calculate the number of chars for
StringArrayWhat changes are included in this PR?
Provide a pub method
num_chars.