[R] Matching/checking for occurence when values are double?

[Matti Viljamaa]

I need to pick from a dataset those rows that have a double value set to 100.
However since the values in this column are like the following:

[1] 121.11750  89.36188 115.44320  99.44964  92.74571 107.90180
[7] 138.89310 125.14510  81.61953  95.07307  88.57700  94.85971
[13]  88.96280 114.11430 100.53410 120.41910 114.42690
…

Then can I match against 100 or 100.0? Or do I need to match against 100.00000 or something else?

E.g. does 

100.0 %in% kidmomiq$mom_iq 

produce a truthful match result with this kind of data (I’m getting 0 occurrences, which might be correct, but I’m not sure)?