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" …

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 …

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 …

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.

15 Ok, lets check the man pages: df - report file system disk space usage and du - estimate file space usage Those two tools were meant for different propose. While df is to show the file …

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 …

Mar 11, 2019 · df[2] #Column<third col> 3. pyspark.sql.functions.col This is the Spark native way of selecting a column and returns a expression (this is the case for all column functions) which …

I want to set the dtypes of multiple columns in pd.Dataframe (I have a file that I've had to manually parse into a list of lists, as the file was not amenable for pd.read_csv) import pandas as pd ...

Dec 28, 2014 · So any changes made to df` or df2 will be made to the same object instance. Whereas in the df2 = df.copy() a second object instance is created, a copy of the first one, but …

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 …