Question: ```
NEI <- readRDS(unz(tf, filename = "summarySCC_PM25.rds", open = "", encoding = getOption("encoding")))

```

*Variable tf* is a **temporary** file with a very specific location saved on the hard drive. It is my understanding that the format for [unz()](http://astrostatistics.psu.edu/su07/R/html/base/html/connections.html "unz() documentation") is:

```
unz(description, filename, open = "", encoding = getOption("encoding"))

```

As I read the documentation, I am interpreting that my application of the code is accurate as that:

1. description is a specific zip file destination, which outputs in *var tf* as c://...//345du.zip
2. filename is summarySCC\_PM25.rds, which is the file to be extracted *from tf*
3. open is already established in the var so black should be fine
4. encoding labels the language type.

Within the context of the code above, I receive "Error: unknown input format" from R 3.1.1. I need clarification on what might be happening as that I interpret my code to be the same as: 

```
NEI <- readRDS("summarySCC_PM25.rds")

```

Am I misinterpreting this?

Answer: 
I found your data online so that I can read your file. It was available from here:

<https://www.linkedin.com/today/post/article/20140617173447-5576436-explore-n-analyze-data-assignment-2>

```
> unzip("C:\\Users\\jmiller\\Downloads\\exdata_data_NEI_data.zip")
> NEI <- readRDS("summarySCC_PM25.rds")
> dim(NEI)
[1] 6497651       6
> colnames(NEI)
[1] "fips"      "SCC"       "Pollutant" "Emissions" "type"      "year"    

```
Avoid unz() and use unzip(withanindex) since the temp file is a moving target