Function arrow_cast::parse::string_to_timestamp_nanos

source · 
pub fn string_to_timestamp_nanos(s: &str) -> Result<i64, ArrowError>
Expand description

Accepts a string in RFC3339 / ISO8601 standard format and some variants and converts it to a nanosecond precision timestamp.

Implements the to_timestamp function to convert a string to a timestamp, following the model of spark SQL’s to_timestamp.

In addition to RFC3339 / ISO8601 standard timestamps, it also accepts strings that use a space to separate the date and time as well as strings that have no explicit timezone offset.

Examples of accepted inputs:

  • 1997-01-31T09:26:56.123Z # RCF3339
  • 1997-01-31T09:26:56.123-05:00 # RCF3339
  • 1997-01-31 09:26:56.123-05:00 # close to RCF3339 but with a space rather than T
  • 1997-01-31T09:26:56.123 # close to RCF3339 but no timezone offset specified
  • 1997-01-31 09:26:56.123 # close to RCF3339 but uses a space and no timezone offset
  • 1997-01-31 09:26:56 # close to RCF3339, no fractional seconds Internally, this function uses the chrono library for the datetime parsing

We hope to extend this function in the future with a second parameter to specifying the format string.

Timestamp Precision

Function uses the maximum precision timestamps supported by Arrow (nanoseconds stored as a 64-bit integer) timestamps. This means the range of dates that timestamps can represent is ~1677 AD to 2262 AM

Timezone / Offset Handling

Numerical values of timestamps are stored compared to offset UTC.

This function interprets strings without an explicit time zone as timestamps with offsets of the local time on the machine

For example, 1997-01-31 09:26:56.123Z is interpreted as UTC, as it has an explicit timezone specifier (“Z” for Zulu/UTC)

1997-01-31T09:26:56.123 is interpreted as a local timestamp in the timezone of the machine. For example, if the system timezone is set to Americas/New_York (UTC-5) the timestamp will be interpreted as though it were 1997-01-31T09:26:56.123-05:00