Convert grib files to text files

[tuxman]

Hi,

I want to read many grib files from a folder, and then save as text files. The name of the text file will be same name as grib file.
My code:

import pygrib, os, glob

LAT1 = None
LAT2 = None
LON1 = None
LON2 = None

def process_message(grb, outfile):
        with open(outfile, 'w') as output:
                tmps = "%s" % grb
                wtitle = tmps.split(':')[1]
                wtime = tmps.split(':')[len(tmps.split(':'))-1].split(' ')[1]
                data, lat, lons = grb.data(LAT1, LAT2, LON1, LON2)
                for i in xrange(len(data)):
                        tdata = data[i]
                        tlat = lat[i]
                        tlon = lons[1]
                for j in xrange(len(tdata)):
                        wdata = tdata[j]
                        wlat = tlat[j]
                        wlon = tlon[j]
                output.write("%s, %s, %s, %s, %s\n" % (wtitle, wtime, wlat, wlon, wdata)) 

os.chdir('/home/george/data')        
filenames = glob.glob('*.grb')

for f in filenames:
        #print f
        grbs = pygrib.open(f)
        grbs.seek(0)
        for grb in grbs:
            grb
            process_message(grb, f)
            os.rename(f, f + '.txt')
        grbs.close()

When I run the code, nothing happens...no errors, no text files was created.
Cheers !

[snippsat]

You are not running script in same folder as files,as you us chdir().
Then have to give absolute path to rename.
Example:

import os

root = '/home/george/data/'
f = 'foo.grb'
print(os.path.join(root, f))

Output:
/home/george/data/foo.grb

Remember that you needs to this for both src and dst parameter in os.rename().

[nilamo]

for f in filenames:
        #print f

If you uncomment that, do you get output?

[tuxman]

Yes, I get the output from line 'print f': the grib files from /data folder.

[snippsat]

Maybe my answer work

/foo
cd1.rgb
cd2.rgb
cd3.rgb

import glob, os
from os.path import join, splitext

root= '/foo'
for f in glob.glob('*.grb'):  
    os.rename(join(root, f), '{}.txt'.format(join(root, splitext(f)[0])))

Output:
/foo
cd1.txt
cd2.txt
cd3.txt

You have to think of this process_message(grb, f) dos it do an in place change of f and return f.

[tuxman]

snippsat, thanks very much for your reply.
My new code:

import pygrib, os, glob
from os.path import join, splitext

LAT1 = None
LAT2 = None
LON1 = None
LON2 = None

def process_message(grb, outfile):
        with open(outfile, 'w') as output:
                tmps = "%s" % grb
                wtitle = tmps.split(':')[1]
                wtime = tmps.split(':')[len(tmps.split(':'))-1].split(' ')[1]
                data, lat, lons = grb.data(LAT1, LAT2, LON1, LON2)
                for i in xrange(len(data)):
                        tdata = data[i]
                        tlat = lat[i]
                        tlon = lons[1]
                for j in xrange(len(tdata)):
                        wdata = tdata[j]
                        wlat = tlat[j]
                        wlon = tlon[j]
                output.write("%s, %s, %s, %s, %s\n" % (wtitle, wtime, wlat, wlon, wdata)) 

root = 'data/'      
os.chdir(root)
    
for f in glob.glob('*.grb'):
        print f
        grbs = pygrib.open(f)
        grbs.seek(0)
        for grb in grbs:
            grb
            process_message(grb, f)
        os.rename(join(root, f), '{}.txt'.format(join(root, splitext(f)[0])))
        grbs.close()

Error:
20150219_083013_.grb

Traceback (most recent call last):
  File "/home/george/mona_modificat/Grib.py", line 35, in <module>
    os.rename(join(root, f), '{}.txt'.format(join(root, splitext(f)[0])))
OSError: [Errno 2] No such file or directory

[nilamo]

Stop using os.chdir(), and just use absolute paths for everything.

Or at least print the old/new paths, since one of them is clearly pointing to nowhere.