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- How can I find the index for a given item in a list?
Caveats Linear time-complexity in list length An index call checks every element of the list in order, until it finds a match If the list is long, and if there is no guarantee that the value will be near the beginning, this can slow down the code This problem can only be completely avoided by using a different data structure
- List of zeros in python - Stack Overflow
How can I create a list which contains only zeros? I want to be able to create a zeros list for each int in range(10) For example, if the int in the range was 4 I will get: [0,0,0,0] and for 7:
- Get unique values from a list in python - Stack Overflow
But that's what we want in order to get the unique elements from a list with duplicates, we want to append them into a new list only when we they came across for a fist time So we really want to evaluate used append(x) only when x is not in used, maybe if there is a way to turn this None value into a truthy one we will be fine, right?
- How do I make a flat list out of a list of lists? - Stack Overflow
If your list of lists comes from a nested list comprehension, the problem can be solved more simply directly by fixing the comprehension; please see How can I get a flat result from a list comprehension instead of a nested list? The most popular solutions here generally only flatten one "level" of the nested list See Flatten an irregular (arbitrarily nested) list of lists for solutions that
- pandas dataframe index: to_list () vs tolist () - Stack Overflow
Note that the question was about pandas tolist vs to_list pandas DataFrame values returns a numpy array and numpy indeed has only tolist Indeed, if you read the discussion about the issue linked in the accepted answer, numpy's tolink is the reason why pandas used tolink and why they did not deprecate it after introducing to_list
- How to concatenate (join) items in a list to a single string
For handling a few strings in separate variables, see How do I append one string to another in Python? For the opposite process - creating a list from a string - see How do I split a string into a list of characters? or How do I split a string into a list of words? as appropriate
- Meaning of list[-1] in Python - Stack Overflow
I have a piece of code here that is supposed to return the least common element in a list of elements, ordered by commonality: def getSingle(arr): from collections import Counter c = Counte
- What is the difference between list and list [:] in python?
When reading, list is a reference to the original list, and list[:] shallow-copies the list When assigning, list (re)binds the name and list[:] slice-assigns, replacing what was previously in the list Also, don't use list as a name since it shadows the built-in
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