HP 50g manual Variables, Subdirectories, Typing variable names

Subdirectories

To store your data in a well organized directory tree you may want to create subdirectories under the HOME directory, and more subdirectories within subdirectories, in a hierarchy of directories similar to folders in modern computers. The subdirectories will be given names that may reflect the contents of each subdirectory, or any arbitrary name that you can think off. For details on manipulation of directories see Chapter 2 in the calculator’s user’s guide.

Variables

Variables are similar to files on a computer hard drive. One variable can store one object (numerical values, algebraic expressions, lists, vectors, matrices, programs, etc). Variables are referred to by their names, which can be any combination of alphabetic and numerical characters, starting with a letter (either English or Greek). Some non-alphabetic characters, such as the arrow (→) can be used in a variable name, if combined with an alphabetical character. Thus, ‘→A’ is a valid variable name, but ‘→’ is not. Valid examples of variable names are: ‘A’, ‘B’, ‘a’, ‘b’, ‘α’, ‘β’, ‘A1’, ‘AB12’, ‘￿A12’, ’Vel’, ’Z0’, ’z1’, etc.

A variable can not have the same name as a function of the calculator. Some of the reserved calculator variable names are the following: ALRMDAT, CST, EQ, EXPR, IERR, IOPAR, MAXR, MINR, PICT, PPAR, PRTPAR, VPAR, ZPAR, der_, e, i, n1,n2, …, s1, s2, …, ΣDAT, ΣPAR, π, ∞.

Variables can be organized into sub-directories (see Chapter 2 in the calculator’s user’s guide).

Typing variable names

To name variables, you will have to type strings of letters at once, which may or may not be combined with numbers. To type strings of characters you can lock the alphabetic keyboard as follows:

~~locks the alphabetic keyboard in upper case. When locked in this fashion, pressing the „ before a letter key produces a lower case letter, while pressing the ‚ key before a letter key produces a special character. If the alphabetic keyboard is already locked in upper case, to lock it in lower case, type, „~.

~~„~ locks the alphabetic keyboard in lower case. When locked in this fashion, pressing the „ before a letter key produces an upper case letter. To unlock lower case, press „~.

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