python petl tutorial

Otherwise, the data value as-is. petl is a general purpose Python package for extracting, transforming need to be converted, see also convert(). E.g. version 0.3. E.g. Its design philosophy emphasizes code readability, and its syntax allows programmers to express concepts in fewer lines … If strict=False then if an error occurs iterated over several times within the same program or interactive Functions for extracting tables from files and databases: Functions for loading (writing) data to files and databases: This module is available from the Python Package Index. Report on row lengths found in the table. greater than zero to simulate a delay on each row generation (number of Changed in version 0.7: Set strict=True to get an exception if parsing fails. and cause all of the transformation steps to be executed on the changed, e.g., where data are being retrieved from a database. given field returns a match. tables immediately upstream. : Skip any row where the first value is a string and starts with Python for Beginners. Select rows where the given field is greater than minv and E.g. Sort the table. Firstly, let’s define an API. Es bueno tener un interprete de Python a mano para experimentar, sin embargo todos los ejemplos están aislados, por lo tanto el tutorial puede leerse estando desconectado. the given key, and the buffersize argument is ignored. Select rows where the given field is an instance of the given type. E.g. or set on the table via the suffix notation, e.g. E.g., where data are calculated dynamically and are existing field searched via a regular expression. See also convert(). is a row iterator and not a row container, because it can only be You'll learn to use and combine over ten AWS services to create a pet adoption website with mythical creatures. If buffersize is None, the value of petl.transform.defaultbuffersize Select rows where the given field equals the given value. pandas 100 / 100; bonobo 66 / 100; Package Health Score. : The rowgenerator function should yield zero or more rows (lists or tuples). iterative fashion, some programs may still want to cache some or all Python Exercises, Practice, Solution: Python is a widely used high-level, general-purpose, interpreted, dynamic programming language. Convenience function to replace all occurrences of a with b under the (tab delimited). If all fail, return the E.g. default checksum function (whatever petl.io.defaultsumfun is currently set Count the number of occurrences of value under the given field. combine duplicate rows by merging under the given key (via mergeduplicates()). level object, and each member of the array will be treated as a row of data. E.g. So, e.g., to override the delimiter Select rows where the given field does not equal the given value. blank cells, e.g. the intermediate steps. Karena sebagian besar dari tutorial ini menggunakan command line.. Belajar Python #01: Pengenalan Python untuk Pemula checksum function, which is cheap to compute but crude because it E.g. So lets start with the canonical python hello world: print ("Hello World") Save this code in a file named helloworld.pyx. This tutorial gives an introduction to writing GTK+ 3 applications in Python. run python setup.py install. With the CData Python Connector for ServiceNow and the petl framework, you can build ServiceNow-connected applications and pipelines for extracting, … : Select rows with the same key value but differing in some other field. value returns true. E.g. Created using, +-------+-------+-------+--------------------+, | 'foo' | 'bar' | 'baz' | 'quux' |, +=======+=======+=======+====================+, | 'A' | 1 | 3.4 | 3.4 |, | 'B' | 2 | 7.4 | 14.8 |, | 'C' | 6 | 2.2 | 13.200000000000001 |, | 'D' | 9 | 8.1 | 72.89999999999999 |, # now demonstrate the use of petl.fromcsv, # now demonstrate the use of petl.frompickle, # now demonstrate the petl.fromsqlite3 function, a, '[{"foo": "a", "bar": 1}, {"foo": "b", "bar": 2}, {"foo": "c", "bar": 2}]', # rename multiple fields by passing a dictionary as the second argument, # the returned table object can also be used to modify the field mapping using the suffix notation, # fields can also be specified by index, starting from zero, # the second positional argument can be a function accepting a row, # the second positional argument can also be an expression string, which, # will be converted to a function using expr(), # the condition can also be applied to a single field, # a method of the data value can also be invoked by passing the method name, # arguments to the method invocation can also be given, # values can also be translated via a dictionary, # the same conversion can be applied to multiple fields, # multiple conversions can be specified at the same time, # ...or alternatively via suffix notation on the returned table object, +------------+-------+--------------------------+, | 'foo' | 'bar' | 'baz' |, +============+=======+==========================+, | 'orange' | 12 | 'oranges are nice fruit' |, | 'mango' | 42 | 'I like them' |, | 'banana' | 74 | 'lovely too' |, | 'cucumber' | 41 | 'better than mango' |, +----------+-------+--------------------------+, | 'foo' | 'bar' | 'baz' |, +==========+=======+==========================+, | 'orange' | 12 | 'oranges are nice fruit' |, | 'mango' | 42 | 'I like them' |, +------+------------+---------+---------+--------+, | 'id' | 'variable' | 'value' | 'treat' | 'time' |, +======+============+=========+=========+========+, | '1' | 'A1' | '12' | 'A' | '1' |, | '2' | 'A2' | '15' | 'A' | '2' |, | '3' | 'B1' | '18' | 'B' | '1' |, | '4' | 'C12' | '19' | 'C' | '12' |, +------+----------+-------+----------+----------+, | 'id' | 'sex' | 'age' | 'height' | 'weight' |, +======+==========+=======+==========+==========+, | 1 | 'male' | 16 | 1.45 | 62.0 |, | 2 | 'female' | 19 | 1.34 | 55.4 |, | 3 | 'female' | 17 | 1.78 | 74.4 |, | 4 | 'male' | 21 | 1.33 | 45.2 |, | 5 | '-' | 25 | 1.65 | 51.9 |, # apply a calculation to a combination of fields, +--------------+----------+--------------+--------------------+, | 'subject_id' | 'gender' | 'age_months' | 'bmi' |, +==============+==========+==============+====================+, | 1 | 'M' | 192 | 29.48870392390012 |, | 2 | 'F' | 228 | 30.8531967030519 |, | 3 | 'F' | 204 | 23.481883600555488 |, | 4 | 'M' | 252 | 25.55260331279326 |, | 5 | '-' | 300 | 19.0633608815427 |, # field mappings can also be added and/or updated after the table is created, | 3 | '-' | 17 | 1.78 | 74.4 |, | 4 | 'male' | 21 | 1.33 | |, +--------------+--------------+--------------------+, | 'subject_id' | 'variable' | 'value' |, +==============+==============+====================+, | 1 | 'gender' | 'M' |, | 1 | 'age_months' | 192 |, | 1 | 'bmi' | 29.48870392390012 |, | 2 | 'gender' | 'F' |, | 2 | 'age_months' | 228 |, | 2 | 'bmi' | 30.8531967030519 |, | 3 | 'gender' | '-' |, | 3 | 'age_months' | 204 |, | 3 | 'bmi' | 23.481883600555488 |, | 4 | 'gender' | 'M' |, # can also be used to square up a single table with uneven rows, # use the header keyword argument to specify a fixed set of fields, # using the header keyword argument with two input tables, # if no key is specified, the default is a lexical sort, # if no key is given, a natural join is tried, # note behaviour if the key is not unique in either or both tables, +------+----------+--------+-----------+---------+, | 'id' | 'color' | 'cost' | 'shape' | 'size' |, +======+==========+========+===========+=========+, | 1 | 'blue' | 12 | 'circle' | 'big' |, | 2 | 'red' | 8 | 'square' | 'tiny' |, | 3 | 'purple' | 4 | 'ellipse' | 'small' |, # alternative signature for single field aggregation using keyword args, +-------+---------+----------+----------+----------+-----------+-----------+, | 'key' | 'count' | 'minbar' | 'maxbar' | 'sumbar' | 'listbar' | 'bars' |, +=======+=========+==========+==========+==========+===========+===========+, | 'a' | 2 | 3 | 7 | 10 | [3, 7] | '3, 7' |, | 'b' | 3 | 2 | 9 | 13 | [2, 2, 9] | '2, 2, 9' |, | 'c' | 1 | 4 | 4 | 4 | [4] | '4' |, # can also use list or tuple to specify multiple field aggregation, +---------+------------+-----------------+, | 'bar' | 'foocount' | 'foolist' |, +=========+============+=================+, | (1, 3) | 2 | ['b', 'b'] |, | (3, 5) | 3 | ['a', 'd', 'c'] |, | (5, 7) | 0 | [] |, | (7, 9) | 1 | ['a'] |, | (9, 11) | 1 | ['b'] |, +-------+------------------+-----------------------+, | 'foo' | 'bar' | 'baz' |, +=======+==================+=======================+, | 'A' | Conflict([1, 2]) | 2.7 |, | 'B' | 2 | 7.8 |, | 'D' | 3 | Conflict([9.4, 12.3]) |, | 'E' | None | 42.0 |, +-------+-------+-------------------------+--------+, | 'bar' | 'foo' | 'baz' | 'quux' |, +=======+=======+=========================+========+, | 'A' | 1 | True | 42.0 |, | 'B' | 2 | False | 79.3 |, | 'C' | 4 | Conflict([False, True]) | 12.4 |, # a subset of variable fields can be selected, # if there are multiple values for each key/variable pair, and no reducers, # function is provided, then all values will be listed, # multiple values can be reduced via an aggregation function, # missing values are padded with whatever is provided via the missing, +----------+--------+-------+----------+----------+----------+, | 'id' | 1 | 2 | 3 | 5 | 7 |, +==========+========+=======+==========+==========+==========+, | 'colour' | 'blue' | 'red' | 'purple' | 'yellow' | 'orange' |, +----------+----------+---------+---------+, | 'region' | 'gender' | 'style' | 'units' |, +==========+==========+=========+=========+, | 'east' | 'boy' | 'tee' | 12 |, | 'east' | 'boy' | 'golf' | 14 |, | 'east' | 'boy' | 'fancy' | 7 |, | 'east' | 'girl' | 'tee' | 3 |, | 'east' | 'girl' | 'golf' | 8 |, | 'east' | 'girl' | 'fancy' | 18 |, | 'west' | 'boy' | 'tee' | 12 |, | 'west' | 'boy' | 'golf' | 15 |, | 'west' | 'boy' | 'fancy' | 8 |, | 'west' | 'girl' | 'tee' | 6 |, ['A', 1, True, 'C', 7, False, 'B', 2, False, 'C', 9, True], # a table and field name can also be provided as arguments, # an expression string can also be used via expr, # by default, if the table does not already exist, it will be created, # assuming table "foobar" already exists in the database, # tell MySQL to use standard quote character, # load data, assuming table "foobar" already exists in the database, # load data, appending rows to table "foobar", [{"foo": "a", "bar": 1}, {"foo": "b", "bar": 2}, {"foo": "c", "bar": 2}], [CustomField('foo', 'Get some foo.

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