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- 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:
- slice - How slicing in Python works - Stack Overflow
The first way works for a list or a string; the second way only works for a list, because slice assignment isn't allowed for strings Other than that I think the only difference is speed: it looks like it's a little faster the first way Try it yourself with timeit timeit () or preferably timeit repeat ()
- 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
- Use a list of values to select rows from a Pandas dataframe
Use a list of values to select rows from a Pandas dataframe Asked 12 years, 11 months ago Modified 4 months ago Viewed 1 8m times
- 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
- How to list all installed packages and their versions in Python?
Is there a way in Python to list all installed packages and their versions? I know I can go inside python Lib site-packages and see what files and directories exist, but I find this very awkward
- What is the syntax to insert one list into another list in python?
What is the syntax to insert one list into another list in python? [duplicate] Asked 14 years, 10 months ago Modified 6 years, 1 month ago Viewed 349k times
- List unique values in a Pandas dataframe - Stack Overflow
You can get the unique values in the whole df with this one-liner: pd Series(df values flatten()) unique() You basically transform your df to a numpy array, flatten and come back to a pandas Series, so you can use unique() However, types might be transformed along the way if you have multiple types in your original df, so be careful
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