| Command Summary | Command Syntax | Calculator Compatibility | Token Size |
|---|---|---|---|
| Tests if one value is smaller than or equal to another. | value1≤value 2 | This command works on all calculators. | 1 byte |
Menu Location
Press [♦][<] to enter ≤.
The ≤ Command
The ≤ operator compares two values, returning true if the right side is greater or if the two are equal, and false otherwise. It is a basic building block of the conditions used by commands such as 68k:If, 68k:when(), and 68k:While. The results of ≤ and the other relational operators (=, ≠, >, ≥, and <) can be combined with the 68k:and, 68k:or, 68k:xor, and 68k:not operators to create more complicated conditions.
It returns a single value for most types of data, and returns false if the two sides are mismatched in type: comparing a single number to a list, for instance, or comparing two lists that are of a different size. The only exception is when comparing two 68k:lists or two 68k:matrices of the same size: in that case, it compares them element-by-element, and returns a list or matrix of true/false values.
:3≤4
true
:3≤2
false
:{1,2,3}≤{3,2,1}
{true true false}
If either side or both contains undefined variables, ≤ will wait to return a value. You can do math with the resulting inequality, and if an operation makes sense, it will be applied to both sides: for instance, if x≤y, then you can negate it to get -x≥-y. An operation will not be applied to both sides if it wouldn't be consistent with the previous inequality: for example, you can't square both sides, since even if x≤y the comparison between x^2 and y^2 could go in any order. You can also extract the two halves of the inequality with 68k:left() and 68k:right().
Advanced Uses
The ≤ operator can also compare strings. It does so by comparing the 68k:character codes of each character, and orders the strings by the first difference it finds. This ideally means that the strings are ordered by dictionary order: for example, "aardvark"≤"apple", since it would come later in the dictionary.
However, the problem is that all uppercase letters have a smaller character code than lowercase letters, so this only holds true if the strings are the same case. Otherwise, strange results can happen: for instance, "Apple"≤"aardvark", since "A" comes before "a".