How to | Use Shorthand Notations

Shorthand notations are a part of the Wolfram Language's rich syntax system that allows multiple ways to feed arguments to functions. In addition to creating compact code, using shorthand notation lets you customize your workflow in the Wolfram Language.

The Wolfram Language provides several convenient methods for entering functions.

For example, use Length with square brackets around a list to get the length of the list:

Using the @ symbol between the function and the list does the same thing. With @ you do not have to move to the end of the expression to match the square bracket:

You can also use the // postfix notation:

These notations extend to any function and any kind of argument:

You can also use infix notation for functions that take two arguments:

    

Pure functions are used very often in the Wolfram Language. They let you use a function without having to define an explicit name for it. You can use the shorthand notation for Function to give a pure function.

Use Function to give a pure function that raises the input to a cubic power:

The # and & symbols can be combined to accomplish the same thing. The # symbol serves as the placeholder for the variable, while the & symbol precedes the value you wish to substitute into the function:

    

Map and Apply are essential to functional programming. Using the shorthand notations for these functions is very convenient.

Use Map to map a function over the elements of a list:

Using /@ does the same thing:

Apply has a shorthand notation as well (@@):

    

Shorthand notations in the Wolfram Language can also be combined to produce efficient code.

Use Map and Function to raise each element of a list to a power and add a symbol to the result:

Perform the same operation using the shorthand notation for Function:

Extend this to include the shorthand notation for Map:

    

You will often need to use previous output in a new computation. This can be done by using the % symbol, the shorthand notation for Out.

Set up a computation:

Use the shorthand notation for Out, the % symbol, to specify the most recent output:

Use % with the shorthand notation for Part, [[...]], to take the first element of the list:

You can use %%% to refer to previous outputs. Get the output generated two computations ago:

If you want to get the output from a computation that is not recent, using many % symbols can be cumbersome.

Instead, use the specific output cell number with Out. If you evaluate this cell, you will get Out[17] from your current Wolfram System session and not necessarily what is shown here:

Here is another shorthand notation:

While convenient, referring to previous output by label or shorthand notation can quickly get out of hand since the current evaluation is always bound to the earlier output. Therefore, you must ensure that the output you want to use is available to your current computation. It is advised that you use this notation with caution.

    

Working with strings can be simplified by using shorthand notations for string manipulation functions.

Joining strings together is a frequently used string operation. Do this with StringJoin:

Using the shorthand notation for StringJoin, <>, this same operation can be written as:

StringExpression is a very important function that is used to represent strings. It is used by a number of string manipulation functions such as StringReplace, StringCases, StringSplit, and StringMatchQ.

Use StringExpression to create a string expression object:

Or directly use ~~, the shorthand notation for StringExpression:

  • Expressions
  • Special Ways to Input Expressions
  • The Syntax of the Wolfram Language
  • Functional Operations
  • Strings and Characters
  • How to: Use the Wolfram Language's Syntax
  • How to: Work with Variables and Functions
  • Function  Map  Apply  Out  Part  StringJoin  StringExpression

  • Wolfram Language Syntax
  • Wolfram Language Syntax Characters
  • Functional Programming
  • String Manipulation
  • "How to" Topics