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The left() Command

Command Summary Command Syntax Calculator Compatibility Token Size
Returns a subsection from the left of a list or string, or the left hand side of an equation. left(equation)
left(list-or-string,length)		 This command works on all calculators. 2 bytes
  • Press 2nd MATH to enter the MATH popup menu.
  • Press 3 to enter the List submenu.
  • Press 9 to select left(.

The left() Command

When applied to a list or a string, left(x,length) gets the first length elements/characters of x. This is an alternative to 68k:mid(), which will do the same thing from any point in the list or string, not just the beginning.

When applied to an equation (such as x=5) or an inequality (such as x<3), left() returns the left-hand side of the equation. This only works for equations that don't get simplified: left(2+2=4) will not work, because 2+2=4 will return 'true' first.

:left({1,2,3,4,5},3)
           {1  2  3}
:left("TI-Basic Developer",8)
           "TI-Basic"
:left(x^2+2x+1>0)
           x^2+2*x+1
:left({1,2,3,4,5},0)
           {}

Optimization

Use left() instead of mid() when the substring starts at the beginning of the list or string.

Error Conditions

260 - Domain error happens when the argument is not a list, string, or equation, or is an equation that has simplified.

Authors: KG