如何使用变量在Python中使用wget下载？

Question

I need to do something like this, but in Python instead of Bash:

i=1
while [ $i <= 10 ] ; do
    wget http://somewebsite.net/shared/fshared_$i.7z
    $i = $i + 1
done

In Python I tried with the following:

import urllib, os
i = 0
while i <= 3:
    os.system('wget http://somewebsite.net/shared/fshared_',i,'.7z')
    i = i + 1

But it does not work, the variable is not concatenated correctly (or something similar).
Using Bash code does not work, apparently in Bash can't do something simple like: i = i + 1

Could anyone help me with this?

SOLVED! :)

Now I have the script both Bash and Python, actually with Python I have several variants.

Thanks to all... thanks a lot ^-^

How do I mark the topic as solved?

Thanks again.

Answer 1

Try

os.system('wget http://somewebsite.net/shared/fshared_%s.7z'%i)

use %s instead of ,

Answer 2

You can increment in Bash. You have to do something like:

i=3
(( i++ ))
echo $i

That last like should print 4. So your script would be:

i=1
while [ $i -le 10 ] ; do
    wget http://somewebsite.net/shared/fshared_$i.7z
    (( i++ ))
done

Edit: fixed code to use -le instead of <= since <= doesn't work in bash.

Answer 3

You can use python without calling out to the shell for each file using urllib

import urllib, os

for i in range(4):
    filename = 'fshared_{}.7z'.format(i)
    urllib.urlretrieve('http://somewebsite.net/shared/'+filename, filename)

Answer 4

Try this

import urllib, os
i = 0
while i <= 3:
    os.system('wget http://somewebsite.net/shared/fshared_%s.7z' % i)
    i = i + 1

Answer 5

To fix the problem with the concatenation, you need to use + to concatenate instead of , , because when you use , to concatenate two strings it separate them with a space character between, the same doesn't happen when you use + because it "really" concatenate the strings.

Eg:

print('Hello' + 'World' + '!')
print('Hello', 'Stack', 'Overflow!')

Output:

HelloWorld!
Hello Stack Overflow!

Your code would look like this now using + instead of , :

#...
os.system('wget http://somewebsite.net/shared/fshared_' + i + '.7z')
#...                                                    ^   ^

Code pasted on Ideone.com

Answer 6

you can also specify python to ask you the url to pass to wget

import os
path = raw_input("enter the url:")
os.system('wget -r -nd -l1 --no-parent -A mp3 %s'%path)

in place of 'mp3' use whatever format you want to download.