def caster(self):
'''Returns a function that takes a row that can be indexed by positions which returns a new
row with all of the values cast to schema types. '''
from ambry.transform import CasterTransformBuilder
bdr = CasterTransformBuilder()
for c in self.columns:
bdr.append(c.name, c.python_type)
return bdr
def test_caster(self):
from ambry.transform import CasterTransformBuilder, NonNegativeInt, NaturalInt
import datetime
ctb = CasterTransformBuilder()
ctb.append('int',int)
ctb.append('float',float)
ctb.append('str',str)
row, errors = ctb({'int':1,'float':2,'str':'3'})
self.assertIsInstance(row['int'],int)
self.assertEquals(row['int'],1)
self.assertTrue(isinstance(row['float'],float))
self.assertEquals(row['float'],2.0)
self.assertTrue(isinstance(row['str'],unicode))
self.assertEquals(row['str'],'3')
# Should be idempotent
row, errors = ctb(row)
self.assertTrue(isinstance(row['int'],int))
self.assertEquals(row['int'],1)
self.assertTrue(isinstance(row['float'],float))
self.assertEquals(row['float'],2.0)
self.assertTrue(isinstance(row['str'],unicode))
self.assertEquals(row['str'],'3')
ctb = CasterTransformBuilder()
ctb.append('date',datetime.date)
ctb.append('time',datetime.time)
ctb.append('datetime',datetime.datetime)
row, errors = ctb({'int':1,'float':2,'str':'3'})
self.assertIsNone(row['date'])
self.assertIsNone(row['time'])
self.assertIsNone(row['datetime'])
row, errors = ctb({'date':'1990-01-01','time':'10:52','datetime':'1990-01-01T12:30'})
self.assertTrue(isinstance(row['date'],datetime.date))
self.assertTrue(isinstance(row['time'],datetime.time))
self.assertTrue(isinstance(row['datetime'],datetime.datetime))
self.assertEquals(row['date'],datetime.date(1990, 1, 1))
self.assertEquals(row['time'],datetime.time(10, 52))
self.assertEquals(row['datetime'],datetime.datetime(1990, 1, 1, 12, 30))
# Should be idempotent
row, errors = ctb(row)
self.assertTrue(isinstance(row['date'],datetime.date))
self.assertTrue(isinstance(row['time'],datetime.time))
self.assertTrue(isinstance(row['datetime'],datetime.datetime))
# Case insensitive
row, errors = ctb({'Date':'1990-01-01','Time':'10:52','Datetime':'1990-01-01T12:30'})
self.assertEquals(row['date'],datetime.date(1990, 1, 1))
self.assertEquals(row['time'],datetime.time(10, 52))
self.assertEquals(row['datetime'],datetime.datetime(1990, 1, 1, 12, 30))
#
# Custom caster types
#
class UpperCaster(str):
def __new__(cls, v):
return str.__new__(cls, v.upper())
ctb = CasterTransformBuilder()
ctb.append('int', int)
ctb.append('float', float)
ctb.append('str', UpperCaster)
ctb.add_type(UpperCaster)
row, errors = ctb({'int': 1, 'float': 2, 'str': 'three'})
self.assertEquals(row['str'], 'THREE')
#
# Handling Errors
#
ctb = CasterTransformBuilder()
ctb.append('int', int)
ctb.append('float', float)
ctb.append('str', str)
ctb.append('ni1', NaturalInt)
ctb.append('ni2', NaturalInt)
row, errors = ctb({'int': '.', 'float': 'a', 'str': '3', 'ni1': 0, 'ni2': 3 },
codify_cast_errors=True)
