Q:

How to get certain phrase from the middle of the string in Python

I have silly question - How can I get just the middle bunch of words? I'm missing with one value.
string = "Here is the content and I want to get middle words"
start = string.index("content")
print(string[start:i'm stucked here!!!])

Any ideas how to count this value to delete the things after content?

A:

The syntax string[start:end] return the sub-sequence of string from index start to end (not included). 
If you want to extract a word that start at the position start and that word is of length n, then the string[start:(start+n)] will return the word.
To get the length of a word, use len(word).
That gives you:
string = "Here is the content and I want to get middle words"
word = "content"
start = string.index(word)
end = start + len(word)
print(string[start:end])

