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- Selecting multiple columns in a Pandas dataframe - Stack Overflow
So your column is returned by df['index'] and the real DataFrame index is returned by df index An Index is a special kind of Series optimized for lookup of its elements' values For df index it's for looking up rows by their label That df columns attribute is also a pd Index array, for looking up columns by their labels
- How do I select rows from a DataFrame based on column values?
Only, when the size of the dataframe approaches million rows, many of the methods tend to take ages when using df[df['col']==val] I wanted to have all possible values of "another_column" that correspond to specific values in "some_column" (in this case in a dictionary)
- How can I iterate over rows in a Pandas DataFrame?
I have a pandas dataframe, df: c1 c2 0 10 100 1 11 110 2 12 120 How do I iterate over the rows of this dataframe? For every row, I want to access its elements (values in cells) by the n
- How do I get the row count of a Pandas DataFrame?
could use df info () so you get row count (# entries), number of non-null entries in each column, dtypes and memory usage Good complete picture of the df If you're looking for a number you can use programatically then df shape [0]
- In pandas, whats the difference between df[column] and df. column?
I'm working my way through Pandas for Data Analysis and learning a ton However, one thing keeps coming up The book typically refers to columns of a dataframe as df['column'] however, sometimes wi
- How to get set a pandas index column title or name?
To just get the index column names df index names will work for both a single Index or MultiIndex as of the most recent version of pandas As someone who found this while trying to find the best way to get a list of index names + column names, I would have found this answer useful:
- python - Shuffle DataFrame rows - Stack Overflow
Doesn't df = df sample(frac=1) do the exact same thing as df = sklearn utils shuffle(df)? According to my measurements df = df sample(frac=1) is faster and seems to perform the exact same action They also both allocate new memory np random shuffle(df values) is the slowest, but does not allocate new memory
- Returning a dataframe in python function - Stack Overflow
df is a local variable You need to assign the result like df = create_df()
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