
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 …
In pandas, what's the difference between df['column'] and …
May 8, 2014 · The book typically refers to columns of a dataframe as df['column'] however, sometimes without explanation the book uses df.column. I don't understand the difference …
How do I get the row count of a Pandas DataFrame?
Apr 11, 2013 · 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 …
How can I iterate over rows in a Pandas DataFrame?
Mar 19, 2019 · 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) …
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" …
Difference between df.where ( ) and df [ (df [ ] == ) ] in pandas ...
Difference between df.where ( ) and df [ (df [ ] == ) ] in pandas , python Asked 9 years, 1 month ago Modified 1 year, 11 months ago Viewed 17k times
python - what’s the difference between df - Stack Overflow
Nov 1, 2021 · I have written a function to show elbow to select the optimal value of K of Kmeans. from sklearn.cluster import KMeans def show_elbow(df): distance_list=[] K = range(1,9) for k in …
python - Renaming column names in Pandas - Stack Overflow
To focus on the need to rename of replace column names with a pre-existing list, I'll create a new sample dataframe df with initial column names and unrelated new column names.
python - What is df.values [:,1:]? - Stack Overflow
Aug 21, 2020 · df.values returns a numpy array with the underlying data of the DataFrame, without any index or columns names. [:, 1:] is a slice of that array, that returns all rows and …
python - df.drop if it exists - Stack Overflow
Nov 30, 2019 · df = df.drop([x for x in candidates if x in df.columns], axis=1) It has the benefit of readability and (with a small tweak to the code) the ability to record exactly which columns …