I'm trying to figure out how to create heatmaps.

I have a csv file that I've imported with 61 observations of 58 variables, formatted as follows and have changed all na values to 0s. 

```none
      T1   T2   T3   T4
1 aaa 3    6    3    0
2 aab 1    8    5    0
3 abb 2    5    0    0
4 bbb 10   0    10   7
5 bbc 8    2    8    1

heat <- data.frame(read.csv("heatdata.csv", header=T))
write.csv(heat,"heat.csv",na="0")
heat <- data.frame(read.csv("heat.csv", header=T))

```

I would like to create heatmaps, both using all of the data in the data frame, as well as specifying particular columns (only T2 and T3, for example). I have tried using both heatmap and heatmap.2 but I obviously don't have my data formatted correctly and am not sure how to handle the data.

```
heatmap(heat2)
Error in heatmap(heat2) : 'x' must be a numeric matrix

```