Function Repository Resource:

# JoinMost

An operator that joins in front of its arguments the sequence of lists it is provided

Contributed by: Seth J. Chandler
 ResourceFunction["JoinMost"][list] an operator that will join the sequence of lists it encounters with list.

## Details and Options

The argument(s) need not have the head List. All subsequent expressions will be joined in front of it provided they have the same head.

## Examples

### Basic Examples

JoinMost uses Join to join its argument {3,4} with whatever else it encounters, which one may think of as Most of the Join:

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JoinMost when used with an association as its argument will override key-value pairs from the sequence of lists it encounters if any of them have the same key:

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### Scope

The operator created by JoinRest using an association can accept a sequence of associations and will override key-value pairs if and only if it encounters any association in the sequence with the same key:

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If JoinMost has no argument, it operates as an identity on the data it is given:

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If JoinMost has a sequence of associations as its argument, it will use the last value for a key it confronts in that sequence to perform the override:

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### Applications

JoinRest can be right composed with Counts to create an Association that coerces an answer for certain anticipated values:

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### Properties and Relations

JoinMost works similarly to Merge with a Last combiner function:

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JoinMost is very similar to the resource function JoinRest. In JoinMost, its argument is placed last in the Join; in JoinRest, its argument is placed first in the Join.

### Possible Issues

JoinMost, like Join, will fail to evaluate if the heads of the expressions to be joined differ from one another:

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### Neat Examples

Why you should read code carefully before trusting the results :

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