This page details several ways to run Embedded Python.
From the Python Shell
You can start the Python shell from an InterSystems Terminal session or from the command line.
Start the Python Shell from Terminal
Start the Python shell from an InterSystems Terminal session by calling the Shell() method of the %SYS.PythonOpens in a new tab class. This launches the Python interpreter in interactive mode. The user and namespace from the Terminal session are passed to the Python shell.
Exit the Python shell by typing the command quit().
The following example launches the Python shell from the USER namespace in a Terminal session. It prints the first few numbers in the Fibonacci sequence and then uses the InterSystems IRIS %SYSTEM.OBJ.ShowClasses() method to print a list of classes in the current namespace.
USER>do ##class(%SYS.Python).Shell()
Python 3.9.5 (default, Jul 6 2021, 13:03:56) [MSC v.1927 64 bit (AMD64)] on win32
Type quit() or Ctrl-D to exit this shell.
>>> a, b = 0, 1
>>> while a < 10:
... print(a, end=' ')
... a, b = b, a+b
...
0 1 1 2 3 5 8 >>>
>>> status = iris.cls('%SYSTEM.OBJ').ShowClasses()
User.Company
User.Person
>>> print(status)
1
>>> quit()
USER>
The method %SYSTEM.OBJ.ShowClasses() returns an InterSystems IRIS %StatusOpens in a new tab value. In this case, a 1 means that no errors were detected.
Start the Python Shell from the Command Line
Start the Python shell from the command line by using the irispython command. This works much the same as starting the shell from Terminal, but you must pass in the InterSystems IRIS username, password, and namespace.
The following example launches the Python shell from the Windows command line:
C:\InterSystems\IRIS\bin>set IRISUSERNAME = <username>
C:\InterSystems\IRIS\bin>set IRISPASSWORD = <password>
C:\InterSystems\IRIS\bin>set IRISNAMESPACE = USER
C:\InterSystems\IRIS\bin>irispython
Python 3.9.5 (default, Jul 6 2021, 13:03:56) [MSC v.1927 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
On UNIX-based systems, use export instead of set.
/InterSystems/IRIS/bin$ export IRISUSERNAME=<username>
/InterSystems/IRIS/bin$ export IRISPASSWORD=<password>
/InterSystems/IRIS/bin$ export IRISNAMESPACE=USER
/InterSystems/IRIS/bin$ ./irispython
Python 3.9.5 (default, Jul 22 2021, 23:12:58)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
Note:
If you see a message saying IRIS_ACCESSDENIED, enable %Service_Callin. In the Management Portal, go to System Administration > Security > Services, select %Service_CallIn, and check the Service Enabled box.
In a Python Script File (.py)
You can also use the irispython command to execute a Python script. Note that in this case, you have to include a step (import iris) that provides access to InterSystems IRIS.
Consider a file C:\python\test.py, on a Windows system, containing the following code:
# print the members of the Fibonacci series that are less than 10
print('Fibonacci series:')
a, b = 0, 1
while a < 10:
print(a, end=' ')
a, b = b, a + b
# import the iris module and show the classes in this namespace
import iris
print('\nInterSystems IRIS classes in this namespace:')
status = iris.cls('%SYSTEM.OBJ').ShowClasses()
print(status)
You could run test.py from the command line, as follows:
C:\InterSystems\IRIS\bin>set IRISUSERNAME = <username>
C:\InterSystems\IRIS\bin>set IRISPASSWORD = <password>
C:\InterSystems\IRIS\bin>set IRISNAMESPACE = USER
C:\InterSystems\IRIS\bin>irispython \python\test.py
Fibonacci series:
0 1 1 2 3 5 8
InterSystems IRIS classes in this namespace:
User.Company
User.Person
1
On UNIX-based systems, use export instead of set.
/InterSystems/IRIS/bin$ export IRISUSERNAME=<username>
/InterSystems/IRIS/bin$ export IRISPASSWORD=<password>
/InterSystems/IRIS/bin$ export IRISNAMESPACE=USER
/InterSystems/IRIS/bin$ ./irispython /python/test.py
Fibonacci series:
0 1 1 2 3 5 8
InterSystems IRIS classes in this namespace:
User.Company
User.Person
1
Note:
If you try to run import iris and see a message saying IRIS_ACCESSDENIED, enable %Service_Callin. In the Management Portal, go to System Administration > Security > Services, select %Service_CallIn, and check the Service Enabled box.
In a Method in an InterSystems IRIS Class
You can write Python methods in an InterSystems IRIS class by using the Language keyword. You can then call the method as you would call a method written in ObjectScript.
For example, take the following class with a class method written in Python:
Class User.EmbeddedPython
{
/// Description
ClassMethod Test() As %Status [ Language = python ]
{
# print the members of the Fibonacci series that are less than 10
print('Fibonacci series:')
a, b = 0, 1
while a < 10:
print(a, end=' ')
a, b = b, a + b
# import the iris module and show the classes in this namespace
import iris
print('\nInterSystems IRIS classes in this namespace:')
status = iris.cls('%SYSTEM.OBJ').ShowClasses()
return status
}
}
You can call this method from ObjectScript:
USER>set status = ##class(User.EmbeddedPython).Test()
Fibonacci series:
0 1 1 2 3 5 8
InterSystems IRIS classes in this namespace:
User.Company
User.EmbeddedPython
User.Person
USER>write status
1
Or from Python:
>>> import iris
>>> status = iris.cls('User.EmbeddedPython').Test()
Fibonacci series:
0 1 1 2 3 5 8
InterSystems IRIS classes in this namespace:
User.Company
User.EmbeddedPython
User.Person
>>> print(status)
1
In SQL Functions and Stored Procedures
You can also write a SQL function or stored procedure using Embedded Python by specifying the argument LANGUAGE PYTHON in the CREATE statement, as is shown below:
CREATE FUNCTION tzconvert(dt TIMESTAMP, tzfrom VARCHAR, tzto VARCHAR)
RETURNS TIMESTAMP
LANGUAGE PYTHON
{
from datetime import datetime
from dateutil import parser, tz
d = parser.parse(dt)
if (tzfrom is not None):
tzf = tz.gettz(tzfrom)
d = d.replace(tzinfo = tzf)
return d.astimezone(tz.gettz(tzto)).strftime("%Y-%m-%d %H:%M:%S")
}
The code uses functions from the Python datetime and dateutil modules.
Note:
On some platforms, the datetime and dateutil modules may not be installed by default. If you run this example and get a ModuleNotFoundError, install the missing modules as described in Install Python Packages.
The following SELECT statement calls the SQL function, converting the current date/time from Eastern time to Coordinated Universal Time (UTC).
SELECT tzconvert(now(), 'US/Eastern', 'UTC')
The function returns something like:
2021-10-19 15:10:05
