[R] ggplot - some questions concerning histograms

[Johannes Radinger]

Hello,

I am a beginner with ggplot and after doing simple graphs (histogram, segments etc.)
some questions came up:

1) I tried to do a histogram, but nothing is displayed although it works with another vector.
I think it is because of the very small values (n=1000, min=1.222e-24 max, 1.890e-20).
I used qplot(variable,geom="histogram")... If do it with the standard plot function it works perfectly.

2) I want to use scale_colour_gradient(). Is there any reference where I can
find the predefined colour-palletes like rainbow etc. and how they look like?

3) How can I change the white grid in the background? In some cases I'd like to
remove the white grid

4) How are the ticks on the X-axis calculated? Can they be changed in a way that
always 5 ticks with the corresponding numbers (labels) are displayed on the X-axis.

Thank you very much

Johannes
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