I wasn't sure under what title to ponder this question exactly, coding golf seems appropriate if a bit unspecific.

I know a little bit of comprehensions in python but they seem very hard to 'read'. The way I see it, a comprehension might accomplish the same as the following code:

for i in range(10): if i == 9: print('i equals 9')

This code is much easier to read than how comprehensions currently work but I've noticed you cant have two : in one line ... this brings me too...

my question:

Is there any way I can get the following example into ONE LINE?

try:
    if sam[0] != 'harry':
        print('hello',  sam)
except:
    pass

Something like this would be great:

try: if sam[0] != 'harry': print('hellp',  sam)
except:pass

But again I encounter the conflicting : I'd also love to know if there's a way to run try (or something like it) without except, it seems entirely pointless that I need to put except:pass in there. its a wasted line.

Unfortunately, what you want is not possible with Python (which makes Python close to useless for command-line one-liner programs). Even explicit use of parentheses does not avoid the syntax exception. You can get away with a sequence of simple statements, separated by semi-colon:

for i in range(10): print "foo"; print "bar"

But as soon as you add a construct that introduces an indented block (like if), you need the line break. Also,

for i in range(10): print "i equals 9" if i==9 else None

is legal and might approximate what you want.

As for the try ... except thing: It would be totally useless without the except. try says "I want to run this code, but it might throw an exception". If you don't care about the exception, leave away the try. But as soon as you put it in, you're saying "I want to handle a potential exception". The pass then says you wish to not handle it specifically. But that means your code will continue running, which it wouldn't otherwise.

You could use the built-in exec statement, eg.:

exec("try: \n \t if sam[0] != 'harry': \n \t\t print('hello',  sam) \nexcept: pass")

Where \n is a newline and \t is used as indentation (a tab).
Also, you should count the spaces you use, so your indentation matches exactly.

However, as all the other answers already said, this is of course only to be used when you really have to put it on one line.

exec is quite a dangerous statement (especially when building a webapp) since it allows execution of arbitrary Python code.

Yes this post is 8 years old, but incase someone comes on here also looking for an answer: you can now just use semicolons. However, you cannot use if/elif/else staments, for/while loops, and you can't define functions. The main use of this would be when using imported modules where you don't have to define any functions or use any if/elif/else/for/while statements/loops.

Here's an example that takes the artist of a song, the song name, and searches genius for the lyrics:

import bs4, requests; song = input('Input artist then song name\n'); print(bs4.BeautifulSoup(requests.get(f'https://genius.com/{song.replace(" ", "-")}-lyrics').text,'html.parser').select('.lyrics')[0].text.strip())

I do not incentivise this, but say you're on command line, you have nothing but Python and you really need a one-liner, you can do this:

python -c "$(echo -e "a='True'\nif a : print 1")"

What we're doing here is pre-processing \n before evaluating Python code.

That's super hacky! Don't write code like this.