Python: is there a C-like for loop available?

Question

Can I do something like this in Python?

for (i = 0; i < 10; i++):
  if someCondition:
     i+=1
  print i

I need to be able to skip some values based on a condition

EDIT: All the solutions so far suggest pruning the initial range in one way or another, based on an already known condition. This is not useful for me, so let me explain what I want to do.

I want to manually (i.e. no getopt) parse some cmd line args, where each 'keyword' has a certain number of parameters, something like this:

for i in range(0,len(argv)):
    arg = argv[i]
    if arg == '--flag1':
       opt1 = argv[i+1]
       i+=1
       continue
    if arg == '--anotherFlag':
       optX = argv[i+1]
       optY = argv[i+2]
       optZ = argv[i+3]
       i+=3
       continue

    ...

Answer 1

Yes, this is how I would do it

>>> for i in xrange(0, 10):
...     if i == 4:
...         continue
...     print i,
...
0 1 2 3 5 6 7 8 9

EDIT
Based on the update to your original question... I would suggest you take a look at optparse

Answer 2

You should use continue to skip a value, in both C and Python.

for i in range(10):
  if someCondition:
     continue
  print(i)

Answer 3

Strange way:

for x in (x for x in xrange(10) if someCondition):
    print str(x)

Answer 4

You probably don't actually need the indices, you probably need the actual items. A better solution would probably be like this:

sequence = 'whatever'
for item in sequence:
    if some_condition:
        continue
    do_stuff_with(item)

Answer 5

 for i in xrange(0, 10):
    if i % 3 == 0
        continue
    print i

Will only values which aren't divisible by 3.

Answer 6

There are two things you could do to solve your problem:

• require comma-separated arguments which are going to be grouped into the following option value, you could use getopt, or any other module then.

• or do more fragile own processing:

  sys.argv.pop()
  cmd = {}
  while sys.argv:
      arg = sys.argv.pop(0)
      if arg == '--arg1':
          cmd[arg] = sys.argv.pop(0), sys.argv.pop(0)
      elif:
          pass
  print(cmd)
  

Answer 7

If you need to iterate over something, and need an index, use enumerate()

for i, arg in enumerate(argv):
    ...

which does the same as the questioner's

for i in range(0,len(argv)):
    arg = argv[i]

Answer 8

Your problem seems to be that you should loop not raw parameters but parsed parameters. I would suggest you to consider to change your decision not to use standard module (like the others).

Answer 9

You could first turn the argv list into a generator:

def g(my_list):
    for item in my_list:
        yield item

You could then step through the items, invoking the generator as required:

my_gen = g(sys.argv[1:]):
while True:
   try:
      arg = my_gen.next()
      if arg == "--flag1":
         optX = my_gen.next()
         opyY = my_gen.next()
         --do something
      elif arg == "--flag2":
         optX = my_gen.next()
         optY = my_gen.next()
         optZ = my_gen.next()
         --do something else
      ...
    except StopIteration:
       break