![]() ![]() We can see a description of our dataframe schema like this: spx. We can then reassign the dataframe variable spx with the new column aliases. In this list comprehension we’re pulling each column object in the Spark dataframe and assigning it an alias that has all the whitespaced removed. The col function returns a column object based on the given name. You can see the complete documentation here: pyspark.sql module Apache Spark has a list of built in functions available for dataframes. Let’s walk through these two lines of code. We can do this in PySpark like this: from import col exprs = spx = spx. There are several ways to do this, but essentially we just want to rename these columns. We can see that there’s a problem with our column names - they are filled with random white space. csv ( 'spx.csv', inferSchema = True, header = True ) spx. from pyspark.sql import SparkSession spark = SparkSession. We’re loading this into a spark dataframe called spx. ![]() Here we’re creating a SparkSession and using it to import a CSV file with historical S&P 500 price data. Installing PySpark isn’t as straightforward as other installations, so if you haven’t installed PySpark yet I recommend reading my tutorial on installing it: Complete Guide to Installing PySpark on MacOS.Ĭreating a Spark object and Importing our. This article is going to focus on typical adhoc data analysis functions using PySpark. What is the most active month for trading volumes?.What is the most that the S&P 500 has ever exceeded its 50-day moving average.What is the biggest intrady price swing?.What day of the week, if any, exhibits the highest returns?.What month has had the highest average daily returns?.What was the lowest daily return for the S&P 500?.What day did the S&P 500 reach it’s highest peak price? What was the peak price?.Creating a spark object and importing our price history.General methods for answering questions about an asset class's price history.How to create and use a user defined function in PySpark.How to create new dataframe columns in PySpark.How to convert date strings to datetime objects.How to import a CSV file into a Spark dataframe object.How to create a Spark session in Python. ![]()
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