I have huge amounts of data to analyze, I tend to leave space between words or variable names as I write my code, So the question is, incases where efficiency is the number
To a first, second, third, ..., approximation, no, it won't cost you any time at all.
The extra time you spend pressing the space bar is orders of magnitude more costly than the cost at run time (and neither matter at all).
The much more significant cost will come from any any decreased readability that results from leaving out spaces, which can make code harder (for humans) to parse.