Question

im makeing something like a check system before run so it meets the requirements with python.
heres my code so far;

def checksystem():
    installednode = os.popen('node ' + srctocoffeecompiler + ' -v')
    // version 1.1.1
    print installednode.read()

i can print the version but is there a better way to check its installed with a version higher then 1.0.x ? heres my code so far to do this.

version = installednode.read()
if installednode.read() == 'CoffeeScript version 1.1.1':
    // the code
    // or split the string with space then get the last array
    // check if its more then 1.1.1 or 111 ( dots removed )

*edit ive read the docs about useing subprocess.Popen, that is maybe better, not sure. im still geting errors no such file exist.

*edit2

pn = subprocess.Popen(['node','-v'], stdout = subprocess.PIPE, stdin = subprocess.PIPE, stderr = subprocess.PIPE)
print "NodeJS version: " + pn.read()

ok, somehow i can call it, but i cant read its output return, same with java

pj = subprocess.Popen(['java','-version'], stdout = subprocess.PIPE, stdin = subprocess.PIPE, stderr = subprocess.PIPE)
print "JAVA: " + pj.read()

thanks!

Answer 1

I would split the version string, the comparison is pretty simple if you use lists:

>>> vers1 = '1.0.1'.split('.')
>>> vers2 = '1.0.0'.split('.')
>>> vers1
['1', '0', '1']
>>> vers2
['1', '0', '0']
>>> vers1 > vers2
True
>>> vers2 > vers1
False
>>> 

Here’s a JavaScript alternative:

>>> var vers1 = "1.0.1".split('.');
>>> var vers2 = "1.0.0".split('.');
>>> vers1
["1", "0", "1"]
>>> vers2
["1", "0", "0"]
>>> vers1 > vers2
true
>>> vers2 > vers1
false

It’s pretty much the same 😉