by H. Fosdick © 2024 RexxInfo.org CC: BY-ND
These charts enumerate equivalences between Rexx and Python. They're for those who know one of these languages and want to learn the other. (This is not intended as an exercise in "which language is better".)
Click here for PDF version.
| Rexx | Python | |
|---|---|---|
| Easy to learn, use, and maintain | Yes | Yes |
| Very powerful | Yes | Yes |
| Open source | Yes | Yes |
| Portable | Yes | Yes |
| Runs on all platforms | Yes | Yes |
| Interfaces to tons of tools | Yes | Yes |
| ANSI or ISO Standard | Yes (ANSI-1996) | No (de facto standard by PEPs) |
| Rexx | Python | |
|---|---|---|
| Dialects | TRL-2, ANSI, Mainframe, ooRexx, NetRexx | Version 2.x, Version 3.x, specialized implementations |
| Unique Usage | * Default scripting language for mainframes and several minor platforms
* Interfaces to all mainframe environments and address spaces |
* Most popular programming language in the world
* Most widely taught language * Ships with many OS's |
| Programming paradigms | Procedural, object-oriented (ooRexx and NetRexx), functional, scripting | Procedural, object-oriented, functional, scripting |
| OOP: classes, objects, multi-inheritance, polymorphism, encapsulation | Yes, in ooRexx and NetRexx | Yes |
| User Group | Rexx Language Association | Python community |
| Quick Online Lookup | Quick Lookup | QuickRef |
| Cheat Sheet (printable PDF) | ANSI Rexx, Mainframe Rexx | Python 3, Cheatography |
| Forum | RexxLA forum | Python forums |
| Further information | RexxInfo.org | Python.org |
Covers ANSI-standard "classic Rexx".
| ANSI Rexx | Python | |
|---|---|---|
| Formatting | Free form | Based on indentation rules |
| Case-sensitive | No | Yes |
| Comments | Enclose inside /* and */ | Start line with # or enclose inside triple quotes (""") |
| Line Continuation | , (comma) | \ (backslash) or implicit |
| Statement Separator | ; (semi-colon) | ; (semi-colon) |
| Code Blocks | Define by do - end | Define by : (colon) plus indentation |
| Undefined Variables | Allowed. Use SYMBOL to determine if a variable has been defined | Undefined variable raises NameError. Circumvent this by assigning special constant None. |
| Assignment Operators | = | = += -= *= /= %= //= **= :=
Compound Bitwise: &= |= ^= >>= <<= |
| Arithmetic Operators | + - * / % ** // | + - * / % ** //
Compound: += -= *= /= %= //= **= |
| Comparison Operators | == \== >> << >>= \<<
<<= \>> = \= <> ><
> < >= \< <= \>
( \ can be replaced with ¬ in any of these) |
== != > < >= <=
Object Identity: is is not |
| Logical Operators | & | && \ (prefix) ¬ (prefix) | and or not |
| Concatenation Operators | || Or concatenate with blank between Or, concatenate by abuttal (no blank) |
+ += * (multiple copies of a string) Concatenate literal strings with blank beween. Use f-strings. Use join or format methods |
| Bitwise Operators | Use built-in functions | & | ^ ~ << >>
Compound: &= |= ^= <<= >>= |
| Membership Operators | Unsupported | in not in |
| Regular Expressions | Use RexxRE Regular Expressions external Library | Use the re module |
| Built-in Functions | About 70 functions | About 70 functions |
| Data Types | Everything's a string, types are reflected in usage | A dynamically typed language with these data types: text (str), numeric (int, float, complex), sequence (list, tuple, range), mapping (dict), set (set, frozenset), boolean (bool), binary (bytes, bytearray, memoryview) |
| Function to Check Data Type | datatype | type |
| Collections of Variables | Use compound variables | list, tuple, range, set, frozenset, dict, bytearray |
| Associative Arrays | Use compound variables | Use a dictionary (dict) |
| Multidimensional Arrays | Use compound variables | Use NumPy library |
| Stack & Queue Operations | Yes (push, pull, parse pull, queue, queued) | Yes (queue module and deque from collections) |
| Decimal Arithmetic | Default | Use the decimal module |
| Flow of Control | if, do, select, call, exit, return, iterate, leave, signal, nop | if, for, while, break, continue, pass, return, exit, quit, match-case |
| Trace Script Execution | trace (instruction), trace (function) | Use the trace or pdb modules |
| Terminate Process | exit | exit() |
| Get User Input | say "Enter your name:" parse pull name | name = input("Enter your name: ") |
| Exception Handling | signal | try-except-else-finally, raise, with |
| Standard Exceptions | novalue, error, failure, halt, notready, syntax, lostdigits | SyntaxError, TypeError, NameError, IndexError, KeyError, ValueError, AttributeError, IOError, ZeroDivisionError, ImportError |
| Run an Operating System Command | Just issue the command string (Rexx passes unrecognized strings to the default active environment) | Use the subprocess module (or older os module) |
Based on Rexx Programmer's Reference, Python Tutorial, and Python Language Reference (v 3.12.3) Thank you to several members of the Rexx LA who gave advice and feedback on this content.
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