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Mastering flat_map in Python with List Comprehension

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Introduction In Python, when working with nested lists or iterables, one common challenge is flattening them into a single list while applying transformations. Many programming languages provide a built-in flatMap function, but Python does not have an explicit flat_map method. However, Python’s powerful list comprehensions offer an elegant way to achieve the same functionality. This article examines implementation behavior using Python’s list comprehensions and other methods. What is flat_map ? Functional programming  flatMap is a combination of map and flatten . It transforms the collection's element and flattens the resulting nested structure into a single sequence. For example, given a list of lists, flat_map applies a function to each sublist and returns a single flattened list. Example in a Functional Programming Language: List(List(1, 2), List(3, 4)).flatMap(x => x.map(_ * 2)) // Output: List(2, 4, 6, 8) Implementing flat_map in Python Using List Comprehension Python’...
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How to verify SSH Installed in Hadoop Cluster Quickly

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Below command helps, whether SSH is installed or not on your Hadoop cluster.

[hadoop-user@master]$ which ssh
/user/bin/bash
[hadoop-user@master] $ which sshd
/user/bin/sshd
[hadoop-user@master] $ which ssh -keygen
/user/bin/sshd

 If you do not get proper response as above. That means that SSH is not installed on your cluster.

Resolution:

If you receive an error message

/user/bin/which: no ssh in (/user/bin: /user/sbin....)

You need to install open SSH (www.openssh.com) vial Linux package manager. Or by downloading the source directly.

Note: This is usually done by System Admin.

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