Python data structure sort list alphabetically
I am a bit confused regarding data structure in python; (),[], and {}. I am trying to sort a simple list, probably since I cannot identify the type of data I am failing to sort it.
My list is simple: ['Stem', 'constitute', 'Sedge', 'Eflux', 'Whim', 'Intrigue']
My question is what type of data this is, and how to sort the words alphabetically?
Answer
[] denotes a list, () denotes a tuple and {} denotes a dictionary. You should take a look at the official Python tutorial as these are the very basics of programming in Python.
What you have is a list of strings. You can sort it like this:
In [1]: lst = ['Stem', 'constitute', 'Sedge', 'Eflux', 'Whim', 'Intrigue']
In [2]: sorted(lst)
Out[2]: ['Eflux', 'Intrigue', 'Sedge', 'Stem', 'Whim', 'constitute']
As you can see, words that start with an uppercase letter get preference over those starting with a lowercase letter. If you want to sort them independently, do this:
In [4]: sorted(lst, key=str.lower)
Out[4]: ['constitute', 'Eflux', 'Intrigue', 'Sedge', 'Stem', 'Whim']
You can also sort the list in reverse order by doing this:
In [12]: sorted(lst, reverse=True)
Out[12]: ['constitute', 'Whim', 'Stem', 'Sedge', 'Intrigue', 'Eflux']
In [13]: sorted(lst, key=str.lower, reverse=True)
Out[13]: ['Whim', 'Stem', 'Sedge', 'Intrigue', 'Eflux', 'constitute']
Please note: If you work with Python 3, then str is the correct data type for every string that contains human-readable text. However, if you still need to work with Python 2, then you might deal with unicode strings which have the data type unicode in Python 2, and not str. In such a case, if you have a list of unicode strings, you must write key=unicode.lower instead of key=str.lower.