I have a text file containing many, many lines of text like `test` in the following:

```
test = "word  123  456    7890.000      0.12000";

```

I would like to extract all of the "string representations of integers." However, I need to be clear about what I would like. In `test` above, I would like the output to be:

```
{"123", "456"}

```

since I am only interested in *actual*, *isolated* (delimited by spaces) string representations of integers. Yes, `7890` is an integer, but in `test` above, it is not isolated, so I do not want my function to return it (since `7890.000` is a decimal).

In the case of `test`, I could use this:

```
StringCases[test, Repeated[DigitCharacter, 3]][[1 ;; 2]]

```

which returns 

```
{"123", "456"}

```

However, this is not general, because my string may contain more than two string representations of integers. So I would like my function to also take this input:

```
test = "word  123  456  123    7890.000      0.12000";

```

and return:

```
{"123", "456", "123"}

```

I have thought about using `StringSplit` followed by `ToExpression` and `IntegerQ`, but this seems like it would be very (unnecessarily?) complicated. Perhaps Mathematica has something better built in that I can use?

Do you have any advice? Thanks!