Question

I’m creating a small script to automatically convert files from .jpg to .png:

import glob, os
import Image

basedir = "C:\Users\User\Desktop\\fimg\images\\"
prefix  = "picture"

def convert_png():
    for jpg in glob.glob(os.path.join(basedir, '*.jpg')):
        filename = f.rsplit('.')[-2]
        njpg = Image.open(basedir + '%s.jpg' % (filename))
        njpg.save(basedir + '%s.png' % (filename))

        print "CONVERTED: " + filename + '.png'

for i, f in enumerate(os.listdir(basedir), 1):
    convert_png()

But with this, it seems to convert the file multiple times (about 10) as it prints the converted message this amount, before moving onto the next file. Is there something wrong here that’s making it do this?

C:\Users\User\Desktop\fimg>python test.py
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 16094.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png
CONVERTED: 185500.png

Answer 1

import glob, os
import Image

basedir = "C:\Users\User\Desktop\\fimg\images\\"
prefix  = "picture"

def convert_png(base):
    njpg = Image.open(basedir + '%s.jpg' % base)
    njpg.save(basedir + '%s.png' % base)
    print "CONVERTED: " + base + '.png'

for i, f in enumerate(os.listdir(basedir), 1):
    base, ext = os.path.splitext(f)
    if ext == '.jpg': # found jpg file
        convert_png(base)

The problem was with the nested loops: The bottom for, which then called convert_png, which itself had another loop. I eliminated the loop in convert_png and simplified the code somewhat by only calling that function when a file with a .jpg extension is found. Note the use of splitext to split the filename into its base and extension.