esay Solutions Ltd Using Formulae

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1 esay Solutions Ltd Using Formulae

2 Contents 1. Basics... 3 Example Form Items and Values... 4 Numbers... 4 Text... 4 Logical... 5 Using Form Items Computing... 7 Operators... 7 Comparing... 7 Order of Precedence... 8 Functions Function Library Arithmetic Functions Logical Functions Date Functions Conversion Functions Text Functions Sub-form Functions Parent Form Function Examples UK Pensioners WorkMobile - Using Formulae

3 1. Basics Each item in a WorkMobile form contains a piece of information, such as some text, a number, a date, and so on. Many types of form item have a formula option. By adding a formula, it will automatically fill itself in with a calculated value. That calculation can be based on the values in other items on the same form. If the mobile user keys something into the item with the formula, the formula is overridden by the keyed information. Example Add two Number items to a form. Give the first one the caption Amount, and the second one the caption Times five. In the second one, add this formula (note that formulae always have an = sign at the start): =Amount * 5 Save the form and publish it. Download the form to your mobile device (or WorkMobile Desktop Edition). Open the form. Type 7 into the Amount box. You should see 35 appear in the Times five box the result of multiplying the seven by five. There might be a short delay before it updates the devices waits a short time to make sure you ve finished typing before it starts calculating. Try changing the value in Amount. Times five will update accordingly. Try keying a value into Times five. Now change Amount. You should see that Times five no longer updates. You can prevent the mobile user from overtyping the value in an item by ticking the read only option for that item in the form designer. WorkMobile - Using Formulae 3

4 2. Form Items and Values As we ve just seen, Number items on a WorkMobile form have a value, which is the number in the box. Likewise, other kinds of item have values too. There are three kinds of value. The kind of value a piece of information has determines what you can and cannot do with it in a formula. Numbers The value of a Number item is the number in the box. Calendar and Time items are also numbers. A Calendar s value a day number, where day 1 is 31st December So, 30th May 2012 is day number 41,059. A Time s value is a fraction of a day. 0 is midnight, midday is 0.5. One number can, therefore, represent a date and a time together. 41,059.5 is midday on the 30th May In a formula, numbers are written simply as numbers. Numbers can be used in a variety of calculations. They can be added, subtracted, multiplied, compared, and so on. Text Most form items are text. Textbox is straightforward. Drop down lists and radio buttons have a value that is the text of the selected item. In a formula, text must be written in double quotes. For example, if we have a drop down list called Gender with the entries Male and Female, we can create a text box with a formula like: ="Hello" & IF(Gender = "Male", "sir", "madam") Two pieces of text can be combined into one, or can be compared. The confusing part can be when a piece of text looks like a number. Typing the same thing into a number box or a text box gives two different results. This is also why they are written differently in a formula. 4 WorkMobile - Using Formulae

5 Some examples: Formula Result Explanation = For numbers, + means addition. ="12" + "15" Error. For text, + has no meaning. ="12" & "15" "1215" & is glue together. Note that the 1215 will appear in the box without the quotes. =12 & 15 Error. & only works on text. For numbers, it has no meaning. =VALUE("12") The VALUE function converts text to a number. This is useful if you have a list of numbers in a drop down list, for example. =VALUE("twelve") + 15 Error. VALUE only works when the number is written in digits it doesn t understand numbers written in words. You will be able to save this, but it will not work on the phone. Logical Checkboxes have logical values these values are either true or false. A checkbox is true if it is ticked, false if it is not. Logical values are also the results of comparing other values. More on this later. Using Form Items In most cases, you will want to use the values from other items on the form. You do this by using the caption of the item from which you want the value. =Age < 18 Note that this is not text data, it a name of a form item, so it doesn t have double-quotes around it. However, if the caption has spaces in it, then you must put single-quotes around it. Same if it has a /, +, - or any other special symbol. = Age at last birthday < 18 The name needs to match exactly. If the caption is Age, then you must write Age, not age. The form designer will complain if it cannot find an item with the caption you ve given. WorkMobile - Using Formulae 5

6 For best results: Only take values from items before (above) the one for which you are writing the formula. Avoid having double or single quotes in captions. Don t have two items on a form with the same caption if you want to use them in a formula. Watch out for double spaces in captions, or a space at the end. 6 WorkMobile - Using Formulae

7 3. Computing Operators Operators are probably the most familiar way of computing new values from existing ones. Operator Action Works on Example Result ^ To the power of Numbers =12^2 144 * Multiply Numbers =6 * 9 54 / Divide Numbers =12 / Add Numbers = Subtract Numbers =9-4 5 & Glue Text ="Hel" & "lo" "Hello" = Equal Any =3 = 12 ="Dog" = "Boy" <> Not equal Any =3 <> 12 ="Dog" <> "Boy" < Less than Any =3 < 12 ="Dog" < "Boy" > Greater than Any =3 > 12 ="Dog" > "Boy" False False True True True False False True Gluing text together with & does not add a space. If you need a space, remember to add one to the end of the first text item, or the beginning of the next. Comparing =, <>, < and > are used for comparing values. You can also use <= (less than or equal) and >= (greater than or equal). The result of comparing is always a logical (true or false) type value. When you compare text, less than usually means alphabetically before, which is why Boy is less than Dog (B comes before D). Because dates and times are just numbers, they are compared as numbers. Since smaller numbers mean earlier dates (or times), less than can be read as earlier than (and, likewise, greater than becomes later than ). WorkMobile - Using Formulae 7

8 Order of Precedence This idea might have been taught to you at school as BODMAS, BIDMAS, BEDMAS or PEMDAS. Mnemonic Alternative Name Symbols B P Brackets (parenthesis) ( ) O E Order (exponents) ^ DM MD Multiplication, Division *, / AS AS Addition, Subtraction +, - This is the order in which parts of the calculation happen. Things higher up the list get done first. Where two things are at the same level (like multiplication and division), they are done from left to right. =4 + 5 * 6 It s easy to fall into the trap of think that this is = 9, and then 9 * 6 = 54. But, because multiplication comes first, it is actually 5 * 6 = 30, = 34. If you actually wanted 54 as the result, this is where brackets come in. =(4 + 5) * 6 Anything in brackets always has priority. The more brackets, the higher the priority. Now, the part happens first, because it has more brackets around it than the multiplication. If in doubt, add brackets. Other rules: All comparison operators have the same priority, and it is less than add and subtract. Where a - sign is used to make a number negative (rather than to subtract), it has priority over everything except brackets. -3^2, therefore, is 9, not -9. Functions always have the lowest priority, and all have the same priority. Avoid very long formulae by breaking them up into steps and using hidden text or number items to hold the intermediate values. Functions A function is written as a word, followed by brackets containing a list of values. If there is more than one value, then they are separated by commas. How many values are needed depends on the function. There is a predefined list of functions, each with a special purpose. =MIN(6, 9) The MIN function takes two numbers, and results in the MINimum of the two. In this case, 6. =2 * MIN(5 + 1, 12 3) This formula works out to WorkMobile - Using Formulae

9 If you want the minimum of three numbers, you need to nest two MIN functions. =MIN(6, MIN(9, 15)) Things in brackets get done first, to first the MIN(9, 15) happens (works out to 9), then the MIN(6, 9) part (works out to 6). You can mix different functions and operators however you like, provided you put everything in the right place. =9 * MIN(4 * 2, MAX(VALUE("7"), 36 / 6) + 3) 2 Try copying that formula into a cell of your favourite spreadsheet application. WorkMobile - Using Formulae 9

10 4. Function Library Arithmetic Functions 10 WorkMobile - Using Formulae

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14 When you start typing a function, type the name, then both brackets, and go back to fill in the middle. This makes it easier to make sure you have the right number of brackets. Logical Functions 14 WorkMobile - Using Formulae

15 Date Functions For the examples below, we ll assume it s the 30th of May 2012, and it s 6pm (18:00). WorkMobile - Using Formulae 15

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18 Conversion Functions Text Functions 18 WorkMobile - Using Formulae

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20 Sub-form Functions Sub-form functions are used only on a parent form. They calculate values from a complete set of subforms, not one individual sub-form. All sub-form functions want the caption of the sub-form item on this form (not the name of the sub-form s form), and the caption of an item on the sub-form. They all begin with D for data. 20 WorkMobile - Using Formulae

21 Parent Form Function WorkMobile - Using Formulae 21

22 5. Examples UK Pensioners Two items: A number with the caption Age A list with the items Male and Female, and the caption Gender We want to add a page break that will skip the next page if the person is eligible to claim a UK pension based on their age and gender. Under current UK law, a man may claim a state pension at 65, a woman may claim at 60. =IF(Gender = "Male", Age >= 65, Age >= 60) This gives true if the person is a UK pensioner. 22 WorkMobile - Using Formulae