Nushell Niceties: Transform Values Into Semver Types

Nushell can be extended with plugins to have more functionality or types that are not part of standard Nushell. If you want to work with string values that are actually semantic version values (https://semver.org) you can use the Nushell SemVer plugin. The plugin must be added to Nushell by using the command plugin add <location of plugin>. You can check with plugin list command if the plugin is available. This command also shows commands that the plugin adds to Nushell.

The command into semver can be used to convert string values into a semver type. The semver type has 5 properties: major, minor, patch, pre and build. You can use dot notation to get the values for these properties or use the get command. In the following command a string value is transformed to a semver type: let v = '4.0.2' | into semver. And with $v.major you can extract the major part of the semver value and it returns 4.
Records with the keys major, minor, patch, pre and build can be transformed to a semver string with the semver from-record command. And to transform a semver type to a record you can use the command semver into-record.

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Awesome AssertJ: Use isEqualToNormalizingNewlines To Assert With Text Block

A Java text block is an easy way to have a multiline string value. But there is a catch if we want to use a text block with the assertion method isEqualTo. Suppose you have written a piece of code that create a new string value where the line endings are defined using System.lineSeparator(). The string value would have the line ending \n on Linux and MacOS systems, and the line ending \r\n on Windows system. But a Java text block will always use the line ending \n on every platform, including the Windows platform. If you would run your tests on a Windows platform then the assertion using isEqualTo will fail, but the test will pass on Linux or MacOS systems. This is a problem if you are working with developers using different operating systems. Therefore it is better to use the method isEqualToNormalizingNewlines for these type of assertions. AssertJ will make sure the line endings are the same and the tests will pass independent of the operating system the tests are run on.

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Nushell Niceties: Checking If Value Is In List Or String Or Key In Record

Nushell has the in operator to check if a value is an element of list. With the same in operator you can check if a string is a substring of another string. And finally you can use the in operator to check if a key is in a record. When you use the operator the value you want to check is defined before the operator and the list, other string or record is defined after the operator.
The not-in operator is the opposite of the in operator and checks if a value is not in list or other string or key in a record.
It is also possible to use the has and not-has operators to do the same checks, but the value you want to check is set after the operator. The list, other string or record is set before the operator.

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Nushell Niceties: Calculating The Average Of Numeric Values

In order to calculate an average for a list of numbers, file sizes, durations, or range of numbers, or a table with columns containing numeric values you can use the math avg command. This command is part of the math module of Nushell. When the input is a list then the result is a single value with the average of all values in the list. If you use a table as input the result is a record where the key is the column name and the value the average of all values in that column. Finally it is possible to have a single value as input and the result is the same value obviously.

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Nushell Niceties: Calculating The Sum Of Numeric Values

The math module in Nushell has a lot of useful commands to work with numeric values. You can use the math sum command to calculate the sum of a multiple numeric values. The input of the command can be a list of numbers, durations, file sizes, or a range or table with columns containing numeric values. The result is a single numeric value with the sum of all values in the input. The math sum command can also be used on a table with multiple numeric columns. It will return a record with the sum of all values for each column.

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Nushell Niceties: Getting Minimum And Maximum Values

In Nushell we can use a lot a math related commands to get for example the minimum and maximum values of a list of numbers. In the math module you can find the commands math min and math max. You can use these commands to get the minimum and maximum values of a list of numbers, durations, file sizes, a range and tables.

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Nushell Niceties: Checking String Starts Or Ends With Given String

To check if a string value starts or ends with a given string you can use the str starts-with and str ends-with commands. The command returns a boolean value: true if the string starts or ends with the given string and false otherwise. The commands are case sensitive by default. You can use the --ignore-case (or the shorthand -i) to ignore casing while checking if a the string starts or ends with a given string.
To input can be a string value and then that string value is checked. If the input is an array of string values, then each element is checked. It is also possible to check values in a record or table. You need to pass the names of the field(s) or column(s) that you want to check the string values of.

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Nushell Niceties: Tables With Different Themes

A lot of commands have output displayed as table. It is possible to use different themes for tables. If you run the command table --list you get all available themes. At the moment the following themes are available: basic, compact, compact_double, default, heavy, light, none, reinforced, rounded, thin, with_love, psql, markdown, dots, restructured, ascii_rounded, basic_compact, single, double. You can use a theme with the table command by using the --theme option and the name of the theme. For example to have a different table theme for the ls command you can use ls | table --theme light.
If you want to change the theme for all table output you can set the configuration option $env.config.table.mode. To make this configuration setting permanent you can add it to config.nu file.

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Nushell Niceties: Summon Ellie The Nushell Mascot

When you start Nushell you can see a nice ASCII art elephant. That is Ellie a cute and friendly elephant mascot for Nushell. Elephants are popular as you can see them in other products like Mastodon and Gradle. It is possible to summon Ellie in your Nushell environment by running the ellie command. This command is part of the std library and you need to run use std ellie or std use * first.

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Nushell Niceties: Checking For Emptiness

To check if a value is empty you can use the is-empty command. The command can be used for string values, lists and records.
The opposite check to see if a value is not empty can be done with the is-not-empty command. Just like with the is-empty command this can be used for string values, lists and records. To check if values in a table column are not empty the names of the columns to check can be passed as argument.

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