How-to articles, tricks, and solutions about PANDAS

"Large data" workflows using pandas

Here is an example of a workflow for handling large data using the pandas library:

Change column type in pandas

In pandas, you can change the data type of a column using the astype() function.

Combine two columns of text in pandas dataframe

In pandas, you can use the str.cat() function to combine the values of two columns of text into a single column.

Convert columns to string in Pandas

To convert all columns in a Pandas DataFrame to strings, you can use the following code snippet:

Convert floats to ints in Pandas?

To convert floats to integers in Pandas, you can use the astype() function.

Convert list of dictionaries to a pandas DataFrame

Here is an example of how to convert a list of dictionaries to a pandas DataFrame:

Convert Pandas Column to DateTime

To convert a column in a Pandas DataFrame to a datetime data type, you can use the pandas.to_datetime() function.

Convert pandas dataframe to NumPy array

In pandas, you can convert a DataFrame to a NumPy array by using the values attribute.

Convert Python dict into a dataframe

You can use the Pandas library to convert a Python dictionary into a dataframe.

Converting a Pandas GroupBy output from Series to DataFrame

Here is an example code snippet that demonstrates how to convert the output of a Pandas GroupBy operation from a Series to a DataFrame:

Count the frequency that a value occurs in a dataframe column

Here is an example code snippet that counts the frequency of values in a column of a Pandas DataFrame:

Create a Pandas Dataframe by appending one row at a time

Here is an example of creating a Pandas DataFrame by appending one row at a time:

Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers?

To create a Pandas DataFrame from a Numpy array and specify the index column and column headers, you can use the pd.DataFrame() constructor and pass in the Numpy array, as well as the index, columns parameters.

Creating an empty Pandas DataFrame, and then filling it

Note that in above example, the DataFrame is created empty first, and then columns are added one by one using the assignment operator (=).

Delete a column from a Pandas DataFrame

You can delete a column from a Pandas DataFrame using the drop function.

Deleting DataFrame row in Pandas based on column value

In Pandas, you can delete a row in a DataFrame based on a certain column value by using the drop() method and passing the index label of the row you want to delete.

Extracting just Month and Year separately from Pandas Datetime column

You can extract the month and year separately from a Pandas datetime column using the dt accessor.

Extracting specific selected columns to new DataFrame as a copy

To create a new DataFrame with a subset of columns from an existing DataFrame, you can use the pandas library.

Filter pandas DataFrame by substring criteria

Here is an example of how you can filter a pandas DataFrame by substring criteria:

Get a list from Pandas DataFrame column headers

You can use the DataFrame.columns attribute to access the column labels of a DataFrame as an Index object.

Get first row value of a given column

Here's an example of how you can get the first row value of a given column in a Pandas DataFrame in Python:

Get list from pandas dataframe column or row?

In Pandas, a DataFrame is a 2-dimensional labeled data structure with columns of potentially different types.

Get statistics for each group (such as count, mean, etc) using pandas GroupBy?

In pandas, you can use the groupby() method to group data by one or more columns and then use the agg() method to compute various statistics for each group.

How are iloc and loc different?

iloc and loc are both used to select rows and columns from a Pandas DataFrame, but they work differently.

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