It is inevitable to apply functions and expressions to calculate some data during use of reports. Writing expressions are supported in many places in UReport2. Most typically, we can change the type of the cell to be “expression” and then we can enter the corresponding expression and function in the expression editor below. Moreover, we can also use expressions in conditions, picture sources and QR code data sources etc. in UReport2. The complex statements and reports can only be prepared after we learn and master expressions provided in UReport2.
# Basic syntax
Similar to general programming languages, expressions in UReport2 have some basic data types, such as number and string etc., as shown in the table below:
| Expression type | Description | Example |
| :--- | :--- | :--- |
| Number | It can be either an integer or a decimal | 1, 123 and 0.121331 are all legal numbers |
| String | The string shall be put in single quotes or double quotes | ‘ureport2’, "UReport2” and ‘UReport2 course’ are all legal strings |
| Boolean value | Boolean value represents Yes or No | There are two Boolean values: true & false |
The above three basic data types can be used independently or used in combinatorial calculation by connecting them with “+”, “-”, “\*”, "/” and “%”, as listed in the table below:
| + | Calculate the sum of two numbers or connect two values | 21+31 means to calculate the sum of the two numbers and the result should be 52. “value:”+331 means to connect the two values, and the result should be “value: 331” |
| - | Calculate the difference of two numbers | 21 – 31 indicates calculating the difference between the two numbers, and the result should be -10 |
| \* | Calculate the product of two numbers | 3\*6 results in 18 |
| / | Calculate the division of two numbers | 6/3 results in 2. If one number will not divide into the other number, 8 decimal places shall be kept |
| % | Calculate the residual value of two numbers | 5%3 results in 2; and 6%2 results in 0 |
Almost all languages support the ternary expression judgement, which is clear and simple and makes conditional judgements based on the fewest codes. The syntactic structure of the ternary expression in UReport2 is shown in the figure below:
According to the figure, it is same with ordinary ternary expressions that the first part is about the condition, which may consist of several conditions \(connect them with and or\). The part after “？” is the expression returned after execution when conditions are satisfied. The part after “：” is the expression returned after execution when conditions are not met.
| Examples of ternary expression | Note |
| :--- | :--- |
| A1>1000 ? “normal value" : “low value" | For expression calculation, obtain the value of cell A1 first and judge whether the value is bigger than 1,000. If yes, return to the string of “normal value”, otherwise return to the string of “low value”. |
| A1>1000 and A1<20000 ? “normal value" : “corrected value："+\(A1+100\) | For the condition part, judge whether the value of A1 is greater than 1,000 and lesser than 20,000. If yes, return to the “normal value”, otherwise return to the value of the connection between the string “corrected value” and A1 value adding 100. If A1 is 2,000, then return to the “corrected value：2100” |
According to the figure, if judgement expression consists of the part of if conditional judgement, the judgement with several alternative elseif conditions and finally the part of alternative else conditions. The syntactic structure is similar to java or javascript.
| if\(A1>1000\){return "normal value"} | Judge whether the value of cell A1 is greater than 1,000. If yes, return to the string of “normal value”; and if no, do nothing. |
| if\(A1>1000\){return "normal value"}else{“low value";} | Judge whether the value of cell A1 is greater than 1,000. If yes, return to the string of “normal value”, otherwise return to the string of “low value”. It shall be noted that in if expression, several options of the keyword of return are available. Adding ';’at the end of the row also indicates it is elective. This design is provided mainly to match the habits in java and javascript program. |
| if\(A1>1000 and A1<20000\){ return "normal value:"+A1}else if\(A>20000 and A1<40000\){ return "High value" }else if\(A>20000 and A1<40000\){ return "ultra-high value"}else{ “low value"} | In this case, several combined conditions are added in the part of conditions, and elseif demands multiple judgements. |
Case expression is another form of conditional judgement provided by UReport2. It is similar to if judgement, but is simpler. Its syntactic structure is shown in the figure below:
| case{A1==100 return "normal ", A1>100 and A1<1000 return "normal value", A1>100 and A1<1000 return 'high'} | The two conditions have different values returned |
| case{A1==100 return "normal ", A1>100 and A1<1000 return "normal value", A1>100 and A1<1000 ‘high'} | There are also several options of the keyword of return in the case expression. |
Currently, most calculations in reports are made against cells or are relevant to cells. Since cells in reports are mostly bound to data and data are often multiple, one cell may have multiple values after calculation, making cell reference more complicated. In UReport2, the target cell referred to is calculated relative to the current cell. The name of the cell can be directly written in the expression for cell reference. For example, if referring to cell A1, directly write A1 in the expression. See the example below:
We enter the expression A1 in the cell D1 in the above figure means flling in the cell D1 with the value of cell A1 relative to the current cell D1. Then, the result will be:
Since D1 is the sub-cell to A1, the data that cell A1 is bound to featues the sectional structure. Based on the location of the current cell D1, the result shown in the figure above is reached. If entering B1 in cell D1, the result will be:
Similarly, if entering expression C1 in D1, it will fill in each D1 cell with the value of C1 cell that is located in the same row of D1 cell. The result is not given here.
According to the above example, if referring to the target cell with an expression in a cell in UReport2, the first thing is to judge whether the target cell is located in the same row of column with this cell. If yes, the value of the target cell at the corresponding row or column can be directly applied. If the current cell and the target cell are not in the sam row or column, the situation will be different. Let’s see another example.
In the above example, we enter B1 in the expression of cell C2 to indicate the reference to the value of cell B1. The cell B1 and C2 are not in the same row or column, and cell B1 will have several values after being expanded. However, both cell B1 and cell C2 have a common parent cell or indirect parent cell A1 \(the left parent cell to cell C2 is B2, and the left parent cell to cell B2 is A1, so A1 is the indirect left parent cell to cell C2\), hence all values of B1 under the common parent cell A1 will be applied. The result is shown in the figure below:
Outputs of several values：If more than one value is acquired in UReport2, these values shall be separated with “,” for outputs, as shown in the figure above.
Principle for acquisition of the target cell ：As indicated in the above example, when acquiring the value of the target cell through the expression in a cell in UReport2, the first thing to consider is whether the target cell is located in the same row or column with the current cell. If yes, apply the value of the target cell located in the same row or column. If no, apply all target cells that have a common parent cell with the current cell. If they have a common top parent cell or common left parent cell, apply the target cell in the intersction between the common top parent cell and common left parent cell; and if they do not have a common parent cell, then all target cells after iteration shall be applied.
If we enter C1 in the above cell in the above example, the result will be different. Since C1 is the top parent cell to C2, we directly use the value of the top parent cell located in the same column. The result is shown in the following figure:
Now, let’s look at an example of report:
In the example above, we enter C1 in the expression of cell B2. Since B2 and C2 are not in the same row or column and have no common parent cell, B2 will take all values of cell C1, as shown in the following figure:
Change the parent cell to get the value of a cell：When introducing the report calculation model in the previous video class, we have changed the upper or left parent cell to the current cell several times to realize a common parent cell between the current cell and the target cell. The principle is given here.
