Filter
The Filter function filters a list to include only the elements that satisfy a specific condition.
Parameters
The Filter function accepts two parameters:
- The first parameter is the list to be filtered.
- The second parameter is a function that defines the filtering condition.
Return Value
The Filter function returns a new list containing all the elements from the original list that satisfy the filtering condition.
Examples
Filter[Range[1, 1, 10], Fun[{x}, Greater[x, 5]]]; (* => {6, 7, 8, 9, 10} *)
Filter[{1, 2, 3, 4, 5}, Fun[{x}, Eq[Mod[x, 2], 0]]]; (* => {2, 4} *)
Filter[{#a, #b, #a, #c, #a, #d}, Fun[{x}, Not[Eq[x, #a]]]]; (* => {#b, #c, #d} *)
Find
The Find function is used to locate the index of a specified object within a list.
Parameters
The Find function accepts two parameters:
the first parameter is a list,
and the second parameter is the object to be searched for within the list.
Return Value
If the object is found in the list,
the Find function returns its 1-based index within the list.
If the object is not found, it returns 0.
Examples
Find[{1, 2, 3, 4, 5}, 3]; (* => 3 *)
Find[{"apple", "banana", "cherry"}, "banana"]; (* => 2 *)
Find[{#a, #b, #c}, #a]; (* => 1 *)
Find[{10, 20, 30}, 40]; (* => 0 *)
Find[{}, 5]; (* => 0 *)
Find[{1, 2, 3, 2, 1}, 2]; (* => 2 *)
Floor
The Floor function calculates the floor of a number,
which is the largest integer that is less than or equal to the input number.
Parameters
The Floor function accepts only one numeric parameter.
Return Value
The Floor function returns the floor value of the input number.
Examples
Floor[3.7]; (* => 3 *)
Floor[-3.7]; (* => -4 *)
Floor[-5]; (* => -5 *)
Floor[0.9]; (* => 0 *)
Fun
The Fun function is used to construct anonymous functions, also known as Lambdas.
In KSL, all functions, except for built-in functions and plugin functions, are Lambdas.
Parameters
The Fun function takes two parameters:
the first parameter is a list of symbols, which can be empty, indicating that the function takes no arguments;
the second parameter is the function body, which is the code that the function will execute.
Return Value
The Fun function returns a Lambda function that executes the function body.
Examples
Let[f, Fun[{x}, Sin[Mul[2, x]]]]; (* sin(2 x) *)
Print[f[3]]; (* => -0.27941549819892586 *)