tutorial introduction his provides quick introduction to python the goal is to illustrate most of python' essential features without getting too bogged down in special rules or details to do thisthe briefly covers basic concepts such as variablesexpressionscontrol flowfunctionsgeneratorsclassesand input/output this is not intended to provide comprehensive coverage howeverexperienced programmers should be able to extrapolate from the material in this to create more advanced programs beginners are encouraged to try few examples to get feel for the language if you are new to python and using python you might want to follow this using python instead virtually all the major concepts apply to both versionsbut there are small number of critical syntax changes in python --mostly related to printing and / --that might break many of the examples shown in this section please refer to appendix "python ,for further details running python python programs are executed by an interpreter usuallythe interpreter is started by simply typing python into command shell howeverthere are many different implementations of the interpreter and python development environments (for examplejythonironpythonidleactivepython,wing idepydevetc )so you should consult the documentation for startup details when the interpreter startsa prompt appears at which you can start typing programs into simple read-evaluation loop for examplein the following outputthe interpreter displays its copyright message and presents the user with the promptat which the user types the familiar "hello worldcommandpython rc ( rc : sep : : [gcc (apple inc build )on darwin type "help""copyright""creditsor "licensefor more information print "hello worldhello world lib fl ff