pycassa.util
– Utilities¶
A combination of utilities used internally by pycassa and utilities available for use by others working with pycassa.
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pycassa.util.
convert_time_to_uuid
(time_arg, lowest_val=True, randomize=False)¶ Converts a datetime or timestamp to a type 1
uuid.UUID
.This is to assist with getting a time slice of columns or creating columns when column names are
TimeUUIDType
. Note that this is done automatically in most cases if name packing and value packing are enabled.Also, be careful not to rely on this when specifying a discrete set of columns to fetch, as the non-timestamp portions of the UUID will be generated randomly. This problem does not matter with slice arguments, however, as the non-timestamp portions can be set to their lowest or highest possible values.
Parameters: - datetime (
datetime
or timestamp) – The time to use for the timestamp portion of the UUID. Expected inputs to this would either be adatetime
object or a timestamp with the same precision produced bytime.time()
. That is, sub-second precision should be below the decimal place. - lowest_val (bool) – Whether the UUID produced should be the lowest possible value UUID with the same timestamp as datetime or the highest possible value.
- randomize (bool) – Whether the clock and node bits of the UUID should be randomly generated. The lowest_val argument will be ignored if this is true.
Return type: uuid.UUID
Changed in version 1.7.0: Prior to 1.7.0, datetime objects were expected to be in local time. In 1.7.0 and beyond, naive datetimes are assumed to be in UTC and tz-aware objects will be automatically converted to UTC.
- datetime (
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pycassa.util.
convert_uuid_to_time
(uuid_arg)¶ Converts a version 1
uuid.UUID
to a timestamp with the same precision astime.time()
returns. This is useful for examining the results of queries returning a v1UUID
.Parameters: uuid_arg – a version 1 UUID
Return type: timestamp
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class
pycassa.util.
OrderedDict
(*args, **kwds)¶ A dictionary which maintains the insertion order of keys.
A dictionary which maintains the insertion order of keys.
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clear
() → None. Remove all items from D.¶
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copy
() → a shallow copy of D¶
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classmethod
fromkeys
(S[, v]) → New dict with keys from S and values equal to v.¶ v defaults to None.
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items
() → list of D's (key, value) pairs, as 2-tuples¶
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iteritems
() → an iterator over the (key, value) items of D¶
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iterkeys
() → an iterator over the keys of D¶
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itervalues
() → an iterator over the values of D¶
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keys
() → list of D's keys¶
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pop
(k[, d]) → v, remove specified key and return the corresponding value.¶ If key is not found, d is returned if given, otherwise KeyError is raised
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popitem
() → (k, v), remove and return some (key, value) pair as a¶ 2-tuple; but raise KeyError if D is empty.
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setdefault
(k[, d]) → D.get(k,d), also set D[k]=d if k not in D¶
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update
([E, ]**F) → None. Update D from dict/iterable E and F.¶ If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]
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values
() → list of D's values¶
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