… the estuary stuart floridaĪutomate Excel with Python by KahEm Chu Towards Data … Runtime expressions ($) also get processed during runtime but were designed for use with conditions and expressions. Macro syntax variables ($(var)) get processed during runtime before a task runs. ) get processed at compile time, before runtime starts. Then, after the word macro, you must specify a name for the macro, similar to how you would specify the name of a Python function.Starting with Pig 0.8, some applications such as Oozie workflow invoke Pig using the PigRunner Java class rather than through the command line.SAS Equivalent of Macro variable in Python P = Pig.compile("A = load '" + args + "' as (name, age, gpa) " + P = Pig.compile("A = load '" + sys.argv + "' as (name, age, gpa) " +Īnd in Groovy, pig oovy student.txt: These will become sys.argv in Python and will be passed as main's arguments in Groovy. You can pass command line arguments (the arguments after the script file name) to Python. P = Pig.compile("""A = load '$loadfile' as (name, age, gpa) Ĭurrently this feature is only available in Python and Groovy. For example, you can invoke the below Python script using: pig –param loadfile=student.txt script.py. This variable will be treated as one of the binding variables when binding the Pig Latin script. Similar to regular Pig parameter substitution, you can define parameters using -param/–param_file on Pig's command line. There are two ways to pass parameters to your script: 1. Inside your script, you can define parameters and then pass parameters from command line to your script. The example in the previous section shows how to make use of this call.Īs the case with runSingle, a set of Java Properties or a property file can be passed to the call. In this case, a list of PigStats results is returned – one for each pipeline run. Pig.compile(.).bind(.).runSingle(props)Ī more general version of run allows to run one or more pipelines concurrently. The properties are passed to Pig and a treated as any other properties passed from command line. Additionally, a Java Properties object or a file containing a list of properties can be passed to this call. We have already seen that the simplest way to run a script is to call runSingle without any parameters. Results = Q.run() # it blocks until all pipelines are completed P = Pig.compile("a = load '$in' store a into '$out' ") # COMPILE: compile method returns a Pig object that represents the pipeline Pig will look for the #!/usr/bin/python line in the script. If no argument is specified, it is taken to refer to the reference implementation for Python. If this option is passed as an argument, that argument will refer to the language Pig is embedded in, either Python, JavaScript or Groovy. You can request that embedded Pig be used by adding the -embedded option to the Pig command line. Invocation BasicsĮmbedded Pig is supported in batch mode only, not interactive mode. The exception to this rule is "combined" scripts – here the languages must match (see the Advanced Topics for Python, Advanced Topics for JavaScript and Advanced Topics for Groovy). For example, a Pig Latin statement that registers a Python UDF may be embedded in Python, JavaScript, or Java. Note that host languages and the languages of UDFs (included as part of the embedded Pig) are completely orthogonal. For Groovy, make sure the groovy-all jar is included in your classpath. For JavaScript, make sure the Rhino jar is included in your classpath. For Python, make sure the Jython jar is included in your class path. To enable control flow, you can embed Pig Latin statements and Pig commands in the Python, JavaScript and Groovy scripting languages using a JDBC-like compile, bind, run model.
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