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Python map() and lambda() Use Cases and Examples

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 In Python, map() and lambda functions are often used together for functional programming. Here are some examples to illustrate how they work. Python map and lambda top use cases 1. Using map() with lambda The map() function applies a given function to all items in an iterable (like a list) and returns a map object (which can be converted to a list). Example: Doubling Numbers numbers = [ 1 , 2 , 3 , 4 , 5 ] doubled = list ( map ( lambda x: x * 2 , numbers)) print (doubled) # Output: [2, 4, 6, 8, 10] 2. Using map() to Convert Data Types Example: Converting Strings to Integers string_numbers = [ "1" , "2" , "3" , "4" , "5" ] integers = list ( map ( lambda x: int (x), string_numbers)) print (integers) # Output: [1, 2, 3, 4, 5] 3. Using map() with Multiple Iterables You can also use map() with more than one iterable. The lambda function can take multiple arguments. Example: Adding Two Lists Element-wise list1 = [ 1 , 2 , 3 ]
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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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