I agree that a solution using SelectFirst, FirstPosition, FirstCase might be more 'Wolframian' indeed; but if the OP wants to go the Catch/Throw route--which is not too bad actually--, he can, and quite easily. Moreover I was not sure what version the OP uses; SelectFirst and friends are relatively new...

You can actually give a third argument to SelectFirst in the case it is missing, e.g.:

SelectFirst[Range[2, 7], IntegerQ[11/#] &, "no solution"]

ist doch super

What about this?

Union[Table[If[IntegerQ[21/i], i, False], {i, 2, 5, 1}]] /.  False -> "no solution"

Flatten removes the {} elements in the list returned by Table. So there is then nothing to replace. If you omit Flatten, your example seems to work:

In[1]:= Table[If[IntegerQ[21/i], i, {}], {i, 2, 7, 1}] /. {} -> "No Solution"

Out[1]= {"No Solution", 3, "No Solution", "No Solution", "No Solution", 7}

Sir, Your solution was quite interesting but the output is too heavy for me. It gives all results along with "Integer" or "not an integer"

Do[Print[{21/i, If[IntegerQ[21/i], "integer", "not an integer"]}], {i,   2, 7, 1}]

But I am looking for the following: If the input gives a result, I Print only the integer and maybe only the first integer I catch up But If the input does not give any result, such as

Do[Print[{21/i, If[IntegerQ[21/i], "integer", "not an integer"]}], {i,   2, 5, 1}] 

I only want to print an output such as "No Solution" Is it possible to make so? Thanks for your reply Louis __________

What exactly do you mean by "But, If I use instead a number like ,11," ?

Where do you use this 11?

I must say, that I do not know "wolfram", I use Mathematica. And I have only a faint idea about what you want to do.

Perhaps you should forget this Catch/Throw stuff and and get a result in any case

If[IntegerQ[#], 21/#, ff] & /@ Table[21/i, {i, 2, 7}]

Here you can get what you want.

Union[If[IntegerQ[#], 21/#, ff] & /@ Table[21/i, {i, 2, 7}]]

Get your result:

Part[Union[If[IntegerQ[#], 21/#, ff] & /@ Table[21/i, {i, 2, 7}]], 1]

And now with what I understand you mean by using the number 11

Part[Union[If[IntegerQ[#], 11/#, ff] & /@ Table[11/i, {i, 2, 7}]], 1]

Of course you could use another symbol than ff. Try the commands step by step and see what happens.

Sir, It is very helpful. I am going to make my tests and if ever I got new difficulties I let you know if you do not mind. Thanks very much again for your help Have a good day LOUIS

Sir, Madam, Thanks for your help. The code you provided runs well but it is not exactly what I am looking for.

First exercice, I want to transfer the total output (using the exact initial code you have provided) into an excel file. I have used table=........... then Export["ExcelTest.xlsx, table]. The table is created but the data do not transfer. Can you tell me why? Notice the extension of the file is .xlsx (excel 2016) and not .xls

Second exercice, I want the output corresponding only to the results such 3{integer} and 7{integer} BUT if there is not an integer I want the output to be only showing a result such as {no integer at all}. How do you transform your initial code?

Thanks for your help again, _______________