text stringlengths 81 112k |
|---|
Predict values for a single data point or an RDD of points
using the model trained.
def predict(self, x):
"""
Predict values for a single data point or an RDD of points
using the model trained.
"""
if isinstance(x, RDD):
return x.map(lambda v: self.predict(v)... |
Save this model to the given path.
def save(self, sc, path):
"""
Save this model to the given path.
"""
java_model = sc._jvm.org.apache.spark.mllib.classification.SVMModel(
_py2java(sc, self._coeff), self.intercept)
java_model.save(sc._jsc.sc(), path) |
Load a model from the given path.
def load(cls, sc, path):
"""
Load a model from the given path.
"""
java_model = sc._jvm.org.apache.spark.mllib.classification.SVMModel.load(
sc._jsc.sc(), path)
weights = _java2py(sc, java_model.weights())
intercept = java_mo... |
Train a Naive Bayes model given an RDD of (label, features)
vectors.
This is the Multinomial NB (U{http://tinyurl.com/lsdw6p}) which
can handle all kinds of discrete data. For example, by
converting documents into TF-IDF vectors, it can be used for
document classification. By m... |
Push item onto heap, maintaining the heap invariant.
def heappush(heap, item):
"""Push item onto heap, maintaining the heap invariant."""
heap.append(item)
_siftdown(heap, 0, len(heap)-1) |
Pop the smallest item off the heap, maintaining the heap invariant.
def heappop(heap):
"""Pop the smallest item off the heap, maintaining the heap invariant."""
lastelt = heap.pop() # raises appropriate IndexError if heap is empty
if heap:
returnitem = heap[0]
heap[0] = lastelt
_... |
Pop and return the current smallest value, and add the new item.
This is more efficient than heappop() followed by heappush(), and can be
more appropriate when using a fixed-size heap. Note that the value
returned may be larger than item! That constrains reasonable uses of
this routine unless written... |
Fast version of a heappush followed by a heappop.
def heappushpop(heap, item):
"""Fast version of a heappush followed by a heappop."""
if heap and heap[0] < item:
item, heap[0] = heap[0], item
_siftup(heap, 0)
return item |
Transform list into a heap, in-place, in O(len(x)) time.
def heapify(x):
"""Transform list into a heap, in-place, in O(len(x)) time."""
n = len(x)
# Transform bottom-up. The largest index there's any point to looking at
# is the largest with a child index in-range, so must have 2*i + 1 < n,
# or i... |
Maxheap version of a heappop.
def _heappop_max(heap):
"""Maxheap version of a heappop."""
lastelt = heap.pop() # raises appropriate IndexError if heap is empty
if heap:
returnitem = heap[0]
heap[0] = lastelt
_siftup_max(heap, 0)
return returnitem
return lastelt |
Maxheap version of a heappop followed by a heappush.
def _heapreplace_max(heap, item):
"""Maxheap version of a heappop followed by a heappush."""
returnitem = heap[0] # raises appropriate IndexError if heap is empty
heap[0] = item
_siftup_max(heap, 0)
return returnitem |
Transform list into a maxheap, in-place, in O(len(x)) time.
def _heapify_max(x):
"""Transform list into a maxheap, in-place, in O(len(x)) time."""
n = len(x)
for i in reversed(range(n//2)):
_siftup_max(x, i) |
Maxheap variant of _siftdown
def _siftdown_max(heap, startpos, pos):
'Maxheap variant of _siftdown'
newitem = heap[pos]
# Follow the path to the root, moving parents down until finding a place
# newitem fits.
while pos > startpos:
parentpos = (pos - 1) >> 1
parent = heap[parentpos]
... |
Maxheap variant of _siftup
def _siftup_max(heap, pos):
'Maxheap variant of _siftup'
endpos = len(heap)
startpos = pos
newitem = heap[pos]
# Bubble up the larger child until hitting a leaf.
childpos = 2*pos + 1 # leftmost child position
while childpos < endpos:
# Set childpos to i... |
Merge multiple sorted inputs into a single sorted output.
Similar to sorted(itertools.chain(*iterables)) but returns a generator,
does not pull the data into memory all at once, and assumes that each of
the input streams is already sorted (smallest to largest).
>>> list(merge([1,3,5,7], [0,2,4,8], [5,... |
Find the n smallest elements in a dataset.
Equivalent to: sorted(iterable, key=key)[:n]
def nsmallest(n, iterable, key=None):
"""Find the n smallest elements in a dataset.
Equivalent to: sorted(iterable, key=key)[:n]
"""
# Short-cut for n==1 is to use min()
if n == 1:
it = iter(ite... |
Find the n largest elements in a dataset.
Equivalent to: sorted(iterable, key=key, reverse=True)[:n]
def nlargest(n, iterable, key=None):
"""Find the n largest elements in a dataset.
Equivalent to: sorted(iterable, key=key, reverse=True)[:n]
"""
# Short-cut for n==1 is to use max()
if n ==... |
Compute the correlation matrix with specified method using dataset.
:param dataset:
A Dataset or a DataFrame.
:param column:
The name of the column of vectors for which the correlation coefficient needs
to be computed. This must be a column of the dataset, and it must cont... |
Given a list of metrics, provides a builder that it turns computes metrics from a column.
See the documentation of [[Summarizer]] for an example.
The following metrics are accepted (case sensitive):
- mean: a vector that contains the coefficient-wise mean.
- variance: a vector tha co... |
Returns an aggregate object that contains the summary of the column with the requested
metrics.
:param featuresCol:
a column that contains features Vector object.
:param weightCol:
a column that contains weight value. Default weight is 1.0.
:return:
an aggrega... |
Compute the correlation (matrix) for the input RDD(s) using the
specified method.
Methods currently supported: I{pearson (default), spearman}.
If a single RDD of Vectors is passed in, a correlation matrix
comparing the columns in the input RDD is returned. Use C{method=}
to spec... |
Creates a list of callables which can be called from different threads to fit and evaluate
an estimator in parallel. Each callable returns an `(index, metric)` pair.
:param est: Estimator, the estimator to be fit.
:param train: DataFrame, training data set, used for fitting.
:param eva: Evaluator, used... |
Sets the given parameters in this grid to fixed values.
Accepts either a parameter dictionary or a list of (parameter, value) pairs.
def baseOn(self, *args):
"""
Sets the given parameters in this grid to fixed values.
Accepts either a parameter dictionary or a list of (parameter, value)... |
Builds and returns all combinations of parameters specified
by the param grid.
def build(self):
"""
Builds and returns all combinations of parameters specified
by the param grid.
"""
keys = self._param_grid.keys()
grid_values = self._param_grid.values()
... |
Return Python estimator, estimatorParamMaps, and evaluator from a Java ValidatorParams.
def _from_java_impl(cls, java_stage):
"""
Return Python estimator, estimatorParamMaps, and evaluator from a Java ValidatorParams.
"""
# Load information from java_stage to the instance.
esti... |
Return Java estimator, estimatorParamMaps, and evaluator from this Python instance.
def _to_java_impl(self):
"""
Return Java estimator, estimatorParamMaps, and evaluator from this Python instance.
"""
gateway = SparkContext._gateway
cls = SparkContext._jvm.org.apache.spark.ml.p... |
Given a Java CrossValidator, create and return a Python wrapper of it.
Used for ML persistence.
def _from_java(cls, java_stage):
"""
Given a Java CrossValidator, create and return a Python wrapper of it.
Used for ML persistence.
"""
estimator, epms, evaluator = super(Cr... |
Transfer this instance to a Java CrossValidator. Used for ML persistence.
:return: Java object equivalent to this instance.
def _to_java(self):
"""
Transfer this instance to a Java CrossValidator. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
... |
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
It does not copy the extra Params into the subModels.
:para... |
setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,\
parallelism=1, collectSubModels=False, seed=None):
Sets params for the train validation split.
def setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,
... |
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies creates a deep copy of
the embedded paramMap, and copies the embedded and extra parameters over.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
de... |
Given a Java TrainValidationSplit, create and return a Python wrapper of it.
Used for ML persistence.
def _from_java(cls, java_stage):
"""
Given a Java TrainValidationSplit, create and return a Python wrapper of it.
Used for ML persistence.
"""
estimator, epms, evaluato... |
Transfer this instance to a Java TrainValidationSplit. Used for ML persistence.
:return: Java object equivalent to this instance.
def _to_java(self):
"""
Transfer this instance to a Java TrainValidationSplit. Used for ML persistence.
:return: Java object equivalent to this instance.
... |
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
And, this creates a shallow copy of the validationMetrics.
I... |
Given a Java TrainValidationSplitModel, create and return a Python wrapper of it.
Used for ML persistence.
def _from_java(cls, java_stage):
"""
Given a Java TrainValidationSplitModel, create and return a Python wrapper of it.
Used for ML persistence.
"""
# Load informat... |
Transfer this instance to a Java TrainValidationSplitModel. Used for ML persistence.
:return: Java object equivalent to this instance.
def _to_java(self):
"""
Transfer this instance to a Java TrainValidationSplitModel. Used for ML persistence.
:return: Java object equivalent to this ins... |
Returns the value of Spark runtime configuration property for the given key,
assuming it is set.
def get(self, key, default=_NoValue):
"""Returns the value of Spark runtime configuration property for the given key,
assuming it is set.
"""
self._checkType(key, "key")
if d... |
Assert that an object is of type str.
def _checkType(self, obj, identifier):
"""Assert that an object is of type str."""
if not isinstance(obj, basestring):
raise TypeError("expected %s '%s' to be a string (was '%s')" %
(identifier, obj, type(obj).__name__)) |
Create a PySpark function by its name
def _create_function(name, doc=""):
"""Create a PySpark function by its name"""
def _(col):
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)(col._jc if isinstance(col, Column) else col)
return Column(jc)
_.__name__ =... |
Similar with `_create_function` but creates a PySpark function that takes a column
(as string as well). This is mainly for PySpark functions to take strings as
column names.
def _create_function_over_column(name, doc=""):
"""Similar with `_create_function` but creates a PySpark function that takes a column... |
Wrap the deprecated function to print out deprecation warnings
def _wrap_deprecated_function(func, message):
""" Wrap the deprecated function to print out deprecation warnings"""
def _(col):
warnings.warn(message, DeprecationWarning)
return func(col)
return functools.wraps(func)(_) |
Create a binary mathfunction by name
def _create_binary_mathfunction(name, doc=""):
""" Create a binary mathfunction by name"""
def _(col1, col2):
sc = SparkContext._active_spark_context
# For legacy reasons, the arguments here can be implicitly converted into floats,
# if they are not ... |
Create a window function by name
def _create_window_function(name, doc=''):
""" Create a window function by name """
def _():
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)()
return Column(jc)
_.__name__ = name
_.__doc__ = 'Window function: ' + doc... |
Aggregate function: returns a new :class:`Column` for approximate distinct count of
column `col`.
:param rsd: maximum estimation error allowed (default = 0.05). For rsd < 0.01, it is more
efficient to use :func:`countDistinct`
>>> df.agg(approx_count_distinct(df.age).alias('distinct_ages')).collec... |
Marks a DataFrame as small enough for use in broadcast joins.
def broadcast(df):
"""Marks a DataFrame as small enough for use in broadcast joins."""
sc = SparkContext._active_spark_context
return DataFrame(sc._jvm.functions.broadcast(df._jdf), df.sql_ctx) |
Returns a new :class:`Column` for distinct count of ``col`` or ``cols``.
>>> df.agg(countDistinct(df.age, df.name).alias('c')).collect()
[Row(c=2)]
>>> df.agg(countDistinct("age", "name").alias('c')).collect()
[Row(c=2)]
def countDistinct(col, *cols):
"""Returns a new :class:`Column` for distinct... |
Aggregate function: returns the last value in a group.
The function by default returns the last values it sees. It will return the last non-null
value it sees when ignoreNulls is set to true. If all values are null, then null is returned.
.. note:: The function is non-deterministic because its results dep... |
Returns col1 if it is not NaN, or col2 if col1 is NaN.
Both inputs should be floating point columns (:class:`DoubleType` or :class:`FloatType`).
>>> df = spark.createDataFrame([(1.0, float('nan')), (float('nan'), 2.0)], ("a", "b"))
>>> df.select(nanvl("a", "b").alias("r1"), nanvl(df.a, df.b).alias("r2")).... |
Generates a random column with independent and identically distributed (i.i.d.) samples
from U[0.0, 1.0].
.. note:: The function is non-deterministic in general case.
>>> df.withColumn('rand', rand(seed=42) * 3).collect()
[Row(age=2, name=u'Alice', rand=2.4052597283576684),
Row(age=5, name=u'Bob'... |
Round the given value to `scale` decimal places using HALF_UP rounding mode if `scale` >= 0
or at integral part when `scale` < 0.
>>> spark.createDataFrame([(2.5,)], ['a']).select(round('a', 0).alias('r')).collect()
[Row(r=3.0)]
def round(col, scale=0):
"""
Round the given value to `scale` decimal... |
Shift the given value numBits left.
>>> spark.createDataFrame([(21,)], ['a']).select(shiftLeft('a', 1).alias('r')).collect()
[Row(r=42)]
def shiftLeft(col, numBits):
"""Shift the given value numBits left.
>>> spark.createDataFrame([(21,)], ['a']).select(shiftLeft('a', 1).alias('r')).collect()
[Ro... |
(Signed) shift the given value numBits right.
>>> spark.createDataFrame([(42,)], ['a']).select(shiftRight('a', 1).alias('r')).collect()
[Row(r=21)]
def shiftRight(col, numBits):
"""(Signed) shift the given value numBits right.
>>> spark.createDataFrame([(42,)], ['a']).select(shiftRight('a', 1).alias(... |
Parses the expression string into the column that it represents
>>> df.select(expr("length(name)")).collect()
[Row(length(name)=5), Row(length(name)=3)]
def expr(str):
"""Parses the expression string into the column that it represents
>>> df.select(expr("length(name)")).collect()
[Row(length(name... |
Evaluates a list of conditions and returns one of multiple possible result expressions.
If :func:`Column.otherwise` is not invoked, None is returned for unmatched conditions.
:param condition: a boolean :class:`Column` expression.
:param value: a literal value, or a :class:`Column` expression.
>>> df.... |
Returns the first argument-based logarithm of the second argument.
If there is only one argument, then this takes the natural logarithm of the argument.
>>> df.select(log(10.0, df.age).alias('ten')).rdd.map(lambda l: str(l.ten)[:7]).collect()
['0.30102', '0.69897']
>>> df.select(log(df.age).alias('e'... |
Convert a number in a string column from one base to another.
>>> df = spark.createDataFrame([("010101",)], ['n'])
>>> df.select(conv(df.n, 2, 16).alias('hex')).collect()
[Row(hex=u'15')]
def conv(col, fromBase, toBase):
"""
Convert a number in a string column from one base to another.
>>> df... |
Window function: returns the value that is `offset` rows before the current row, and
`defaultValue` if there is less than `offset` rows before the current row. For example,
an `offset` of one will return the previous row at any given point in the window partition.
This is equivalent to the LAG function in ... |
Window function: returns the ntile group id (from 1 to `n` inclusive)
in an ordered window partition. For example, if `n` is 4, the first
quarter of the rows will get value 1, the second quarter will get 2,
the third quarter will get 3, and the last quarter will get 4.
This is equivalent to the NTILE f... |
Converts a date/timestamp/string to a value of string in the format specified by the date
format given by the second argument.
A pattern could be for instance `dd.MM.yyyy` and could return a string like '18.03.1993'. All
pattern letters of the Java class `java.time.format.DateTimeFormatter` can be used.
... |
Returns the date that is `days` days after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_add(df.dt, 1).alias('next_date')).collect()
[Row(next_date=datetime.date(2015, 4, 9))]
def date_add(start, days):
"""
Returns the date that is `days` days after `start`
... |
Returns the number of days from `start` to `end`.
>>> df = spark.createDataFrame([('2015-04-08','2015-05-10')], ['d1', 'd2'])
>>> df.select(datediff(df.d2, df.d1).alias('diff')).collect()
[Row(diff=32)]
def datediff(end, start):
"""
Returns the number of days from `start` to `end`.
>>> df = s... |
Returns the date that is `months` months after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(add_months(df.dt, 1).alias('next_month')).collect()
[Row(next_month=datetime.date(2015, 5, 8))]
def add_months(start, months):
"""
Returns the date that is `months` months... |
Returns number of months between dates date1 and date2.
If date1 is later than date2, then the result is positive.
If date1 and date2 are on the same day of month, or both are the last day of month,
returns an integer (time of day will be ignored).
The result is rounded off to 8 digits unless `roundOff`... |
Converts a :class:`Column` of :class:`pyspark.sql.types.StringType` or
:class:`pyspark.sql.types.TimestampType` into :class:`pyspark.sql.types.DateType`
using the optionally specified format. Specify formats according to
`DateTimeFormatter <https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTime... |
Returns timestamp truncated to the unit specified by the format.
:param format: 'year', 'yyyy', 'yy', 'month', 'mon', 'mm',
'day', 'dd', 'hour', 'minute', 'second', 'week', 'quarter'
>>> df = spark.createDataFrame([('1997-02-28 05:02:11',)], ['t'])
>>> df.select(date_trunc('year', df.t).alias('yea... |
Returns the first date which is later than the value of the date column.
Day of the week parameter is case insensitive, and accepts:
"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun".
>>> df = spark.createDataFrame([('2015-07-27',)], ['d'])
>>> df.select(next_day(df.d, 'Sun').alias('date')).collect(... |
Returns the last day of the month which the given date belongs to.
>>> df = spark.createDataFrame([('1997-02-10',)], ['d'])
>>> df.select(last_day(df.d).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
def last_day(date):
"""
Returns the last day of the month which the given date be... |
Convert time string with given pattern ('yyyy-MM-dd HH:mm:ss', by default)
to Unix time stamp (in seconds), using the default timezone and the default
locale, return null if fail.
if `timestamp` is None, then it returns current timestamp.
>>> spark.conf.set("spark.sql.session.timeZone", "America/Los_A... |
This is a common function for databases supporting TIMESTAMP WITHOUT TIMEZONE. This function
takes a timestamp which is timezone-agnostic, and interprets it as a timestamp in UTC, and
renders that timestamp as a timestamp in the given time zone.
However, timestamp in Spark represents number of microseconds... |
Bucketize rows into one or more time windows given a timestamp specifying column. Window
starts are inclusive but the window ends are exclusive, e.g. 12:05 will be in the window
[12:05,12:10) but not in [12:00,12:05). Windows can support microsecond precision. Windows in
the order of months are not supporte... |
Calculates the hash code of given columns, and returns the result as an int column.
>>> spark.createDataFrame([('ABC',)], ['a']).select(hash('a').alias('hash')).collect()
[Row(hash=-757602832)]
def hash(*cols):
"""Calculates the hash code of given columns, and returns the result as an int column.
>>>... |
Concatenates multiple input string columns together into a single string column,
using the given separator.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat_ws('-', df.s, df.d).alias('s')).collect()
[Row(s=u'abcd-123')]
def concat_ws(sep, *cols):
"""
Concatenat... |
Computes the first argument into a string from a binary using the provided character set
(one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16').
def decode(col, charset):
"""
Computes the first argument into a string from a binary using the provided character set
(one of 'US-ASCII... |
Formats the number X to a format like '#,--#,--#.--', rounded to d decimal places
with HALF_EVEN round mode, and returns the result as a string.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> spark.createDataFrame([(5,)], ['a']).select(format_number... |
Formats the arguments in printf-style and returns the result as a string column.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> df = spark.createDataFrame([(5, "hello")], ['a', 'b'])
>>> df.select(format_string('%d %s', df.a, df.b).alias('v')).colle... |
Locate the position of the first occurrence of substr column in the given string.
Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>... |
Substring starts at `pos` and is of length `len` when str is String type or
returns the slice of byte array that starts at `pos` in byte and is of length `len`
when str is Binary type.
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
... |
Returns the substring from string str before count occurrences of the delimiter delim.
If count is positive, everything the left of the final delimiter (counting from left) is
returned. If count is negative, every to the right of the final delimiter (counting from the
right) is returned. substring_index per... |
Computes the Levenshtein distance of the two given strings.
>>> df0 = spark.createDataFrame([('kitten', 'sitting',)], ['l', 'r'])
>>> df0.select(levenshtein('l', 'r').alias('d')).collect()
[Row(d=3)]
def levenshtein(left, right):
"""Computes the Levenshtein distance of the two given strings.
>>> ... |
Locate the position of the first occurrence of substr in a string column, after position pos.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
:param substr: a string
:param str: a Column of :class:`pyspark.sql.types.StringType`
:param... |
Left-pad the string column to width `len` with `pad`.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(lpad(df.s, 6, '#').alias('s')).collect()
[Row(s=u'##abcd')]
def lpad(col, len, pad):
"""
Left-pad the string column to width `len` with `pad`.
>>> df = spark.createDataFrame... |
Repeats a string column n times, and returns it as a new string column.
>>> df = spark.createDataFrame([('ab',)], ['s',])
>>> df.select(repeat(df.s, 3).alias('s')).collect()
[Row(s=u'ababab')]
def repeat(col, n):
"""
Repeats a string column n times, and returns it as a new string column.
>>> ... |
Splits str around matches of the given pattern.
:param str: a string expression to split
:param pattern: a string representing a regular expression. The regex string should be
a Java regular expression.
:param limit: an integer which controls the number of times `pattern` is applied.
* ``l... |
r"""Extract a specific group matched by a Java regex, from the specified string column.
If the regex did not match, or the specified group did not match, an empty string is returned.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)-(\d+)', 1).alias('d')).c... |
r"""Replace all substrings of the specified string value that match regexp with rep.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_replace('str', r'(\d+)', '--').alias('d')).collect()
[Row(d=u'-----')]
def regexp_replace(str, pattern, replacement):
r"""Replace all substr... |
A function translate any character in the `srcCol` by a character in `matching`.
The characters in `replace` is corresponding to the characters in `matching`.
The translate will happen when any character in the string matching with the character
in the `matching`.
>>> spark.createDataFrame([('translate... |
Collection function: returns true if the arrays contain any common non-null element; if not,
returns null if both the arrays are non-empty and any of them contains a null element; returns
false otherwise.
>>> df = spark.createDataFrame([(["a", "b"], ["b", "c"]), (["a"], ["b", "c"])], ['x', 'y'])
>>> df... |
Collection function: returns an array containing all the elements in `x` from index `start`
(or starting from the end if `start` is negative) with the specified `length`.
>>> df = spark.createDataFrame([([1, 2, 3],), ([4, 5],)], ['x'])
>>> df.select(slice(df.x, 2, 2).alias("sliced")).collect()
[Row(sli... |
Concatenates the elements of `column` using the `delimiter`. Null values are replaced with
`null_replacement` if set, otherwise they are ignored.
>>> df = spark.createDataFrame([(["a", "b", "c"],), (["a", None],)], ['data'])
>>> df.select(array_join(df.data, ",").alias("joined")).collect()
[Row(joined=... |
Concatenates multiple input columns together into a single column.
The function works with strings, binary and compatible array columns.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat(df.s, df.d).alias('s')).collect()
[Row(s=u'abcd123')]
>>> df = spark.createData... |
Collection function: Locates the position of the first occurrence of the given value
in the given array. Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if the given
value could not be found in the array.
>>> df = spark.creat... |
Collection function: Returns element of array at given index in extraction if col is array.
Returns value for the given key in extraction if col is map.
:param col: name of column containing array or map
:param extraction: index to check for in array or key to check for in map
.. note:: The position i... |
Collection function: Remove all elements that equal to element from the given array.
:param col: name of column containing array
:param element: element to be removed from the array
>>> df = spark.createDataFrame([([1, 2, 3, 1, 1],), ([],)], ['data'])
>>> df.select(array_remove(df.data, 1)).collect()
... |
Returns a new row for each element in the given array or map.
Uses the default column name `col` for elements in the array and
`key` and `value` for elements in the map unless specified otherwise.
>>> from pyspark.sql import Row
>>> eDF = spark.createDataFrame([Row(a=1, intlist=[1,2,3], mapfield={"a": ... |
Extracts json object from a json string based on json path specified, and returns json string
of the extracted json object. It will return null if the input json string is invalid.
:param col: string column in json format
:param path: path to the json object to extract
>>> data = [("1", '''{"f1": "val... |
Creates a new row for a json column according to the given field names.
:param col: string column in json format
:param fields: list of fields to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
... |
Parses a column containing a JSON string into a :class:`MapType` with :class:`StringType`
as keys type, :class:`StructType` or :class:`ArrayType` with
the specified schema. Returns `null`, in the case of an unparseable string.
:param col: string column in json format
:param schema: a StructType or Arra... |
Parses a JSON string and infers its schema in DDL format.
:param json: a JSON string or a string literal containing a JSON string.
:param options: options to control parsing. accepts the same options as the JSON datasource
.. versionchanged:: 3.0
It accepts `options` parameter to control schema inf... |
Parses a CSV string and infers its schema in DDL format.
:param col: a CSV string or a string literal containing a CSV string.
:param options: options to control parsing. accepts the same options as the CSV datasource
>>> df = spark.range(1)
>>> df.select(schema_of_csv(lit('1|a'), {'sep':'|'}).alias("... |
Converts a column containing a :class:`StructType` into a CSV string.
Throws an exception, in the case of an unsupported type.
:param col: name of column containing a struct.
:param options: options to control converting. accepts the same options as the CSV datasource.
>>> from pyspark.sql import Row
... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.