Showing posts with the label Apache Cassandra. Hadoop

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How to Check Column Nulls and Replace: Pandas

Here is a post that shows how to count Nulls and replace them with the value you want in the Pandas Dataframe. We have explained the process in two steps - Counting and Replacing the Null values. Count null values (column-wise) in Pandas ## count null values column-wise null_counts = df.isnull(). sum() print(null_counts) ``` Output: ``` Column1    1 Column2    1 Column3    5 dtype: int64 ``` In the above code, we first create a sample Pandas DataFrame `df` with some null values. Then, we use the `isnull()` function to create a DataFrame of the same shape as `df`, where each element is a boolean value indicating whether that element is null or not. Finally, we use the `sum()` function to count the number of null values in each column of the resulting DataFrame. The output shows the count of null values column-wise. to count null values column-wise: ``` df.isnull().sum() ``` ##Code snippet to count null values row-wise: ``` df.isnull().sum(axis=1) ``` In the above code, `df` is the Panda

8 Top key points in Apache Cassandra in the age of Big data

(Hadoop questions...) Decentralized:  Every knot within the array has the similar part. There is no sole point of letdown. Data is dispersed athwart the array (so every one node holds dissimilar data), however there is no principal as any knot may facility whatever appeal. Supports replication and multi information centre replication: Replication strategic plans are configurable. Cassandra is developed like a dispersed configuration, for distribution of great numerals of nodes athwart numerous information hubs. Key attributes of Cassandra’s dispersed design are especially custom-made for multiple-data centre distribution, for superfluity, for a procedure by which a system automatically transfers control to a duplicate system when it detects a fault or failure and calamity recuperation. Hadoop+Interview+Questions+Part-1 Scalability:  Read and record output either rise linearly as spic-and-span devices are appended, with no layoff either discontinuity to applications. Fault