Processing a dataset is easy in Python.

I’ve been doing more with Python on z/OS, and have spent time using datasets. With the pyzfile package this is very easy! (Before this you had to copy a data set to a file in Unix Services).

You can do all the things you normally expect to do: open, close, read, write, locate, info etc.

from pyzfile import * 
def readfile(): 
   try: 
        with ZFile("//'COLIN.DCOLLECT.OUT'", "rb,type=record,noseek") as file: 
            for kw,value in file.info().items():            
               print(kw,":",value)
            for rec in file: 
               yield  rec 
    except ZFileError as e: 
        print(e,file=sys.stderr) 
                                                                                           
def reader(nrecords): 
    nth = 0                                                                            
    for line in readfile(): 
        nth += 1 
        if  nth > nrecords: 
            break 
        if nth % 100 == 99:
            print("Progress:",nth+1,file=sys.stderr)
        ## Do something..
 

It gave

access_method : QSAM
blksize : 27998
device : DISK
dsname : COLIN.DCOLLECT.OUT
dsorgConcat : False
dsorgHFS : False
dsorgHiper : False
dsorgMem : False
dsorgPDE : False
dsorgPDSdir : False
dsorgPDSmem : False
dsorgPO : False
dsorgPS : True
dsorgTemp : False
dsorgVSAM : False
maxreclen : 1020
mode : {'append': False, 'read': True, 'update': False, 'write': False}
noseek_to_seek : NOSWITCH
openmode : RECORD
recfmASA : False
recfmB : True
recfmBlk : True
recfmF : False
recfmM : False
recfmS : False
recfmU : False
recfmV : True
vsamRKP : 0
vsamRLS : NORLS
vsamkeylen : 0
vsamtype : NOTVSAM
Progress: 100
...

Where the fields are taken from fldata().

Great stuff!

Of course once you’ve got a record, doing something with it may be harder, because , for example Python is ASCII, and you’ll need to convert any character strings from EBCDIC to ASCII.