ngs_get_colvalue: Get values placed separately in column direction
In kikirinrin/gyokaikyor: What the Package Does (One Line, Title Case)

This function return values placed separately on the specific fish row in column direction.

1 2	ngs_get_colvalue(regex, df, offset.x = 0, offset.y = 0, xtract.digit = FALSE)

`regex`	Regular expression to match the name of the target species.
`df`	Loaded Excel sheet
`offset.x`	X-offset of the target value from the position of the month cell
`offset.y`	Y-offest of the target value from the position of the month cell
`xtract.digit`	If `TRUE`, all characters were deleted so that the return value composed only of numerics.