It is hard to explain this without just showing what I have, where I am, and what I need in terms of data structure:
What structure I had:
Where I have got to with my transformation efforts:
What I need to end up with:
Notes:
I've not given actual names for anything as the data is classed as sensitive, but:
Metrics are things that can be measured- for example, the number of permanent or full-time jobs. The number of metrics is larger than presented in the test data (and the example structure above).
Each metric has many years of data (whilst trying to do the code I have restricted myself to just 3 years. The illustration of the structure is based on this test). The number of years captured will change overtime- generally it will increase.
The number of policies will fluctuate, I've just labelled them policy 1, 2 etc for sensitivity reasons and limited the number whilst testing the code. Again, I have limited the number to make it easier to check the outputs.
The source data comes from a workbook of surveys with a tab for each policy. The initial import creates a list of tibbles consisting of a row for each metric, and 4 columns (the metric names, the values for 2024, the values for 2030, and the values for 2035). I converted this to a dataframe, created a vector to be a column header and used cbind() to put this on top to get the "What structure I had" data.
To get to the "Where I have got to with my transformation efforts" version of the table, I removed all the metric columns, created another vector of metrics and used rbind() to put this as the first column.
The idea in my head was to group the data by policy to get a vector for each metric, then transpose this so that the metric became the column, and the grouped data would become the row. Then expand the data to get the metrics repeated for each year. A friend of mine who does coding (but has never used R) has suggested using loops might be a better way forward. Again, I am not sure of the best approach so welcome advice. On Reddit someone suggested using pivot_wider/pivot_longer but this appears to be a summarise tool and I am not trying to summarise the data rather transform its structure.
Any suggestions on approaches or possible tools/functions to use would be gratefully received. I am learning R whilst trying to pull this data together to create a database that can be used for analysis, so, if my approach sounds weird, feel free to suggest alternatives. Thanks
Related
I previously worked on a project where we examined some sociological data. I did the descriptive statistics and after several months, I was asked to make some graphs from the stats.
I made the graphs, but something seemed odd and when I compared the graph to the numbers in the report, I noticed that they are different. Upon investigating further, I noticed that my cleaning code (which removed participants with duplicate IDs) now results with more rows, e.g. more participants with unique IDs than previously. I now have 730 participants, whereas previously there were 702 I don't know if this was due to updates of some packages and unfortunately I cannot post the actual data here because it is confidential, but I am trying to find out who these 28 participants are and what happened in the data.
Therefore, I would like to know if there is a method that allows the user to filter the cases so that the mean of some variables is a set number. Ideally it would be something like this, but of course I know that it's not going to work in this form:
iris %>%
filter_if(mean(.$Petal.Length) == 1.3)
I know that this was an incorrect attempt but I don't know any other way that I would try this, so I am looking for help and suggestions.
I'm not convinced this is a tractable problem, but you may get somewhere by doing the following.
Firstly, work out what the sum of the variable was in your original analysis, and what it is now:
old_sum <- 702 * old_mean
new_sum <- 730 * new_mean
Now work out what the sum of the variable in the extra 28 cases would be:
extra_sum <- new_sum - old_sum
This allows you to work out the relative proportions of the sum of the variable from the old cases and from the extra cases. Put these proportions in a vector:
contributions <- c(extra_sum/new_sum, old_sum/new_sum)
Now, using the functions described in my answer to this question, you can find the optimal solution to partitioning your variable to match these two proportions. The rows which end up in the "extra" partition are likely to be the new ones. Even if they aren't the new ones, you will be left with a sample that has a mean that differs from your original by less than one part in a million.
Good day.
I am 3 month old in R and R-Studio but am getting the hang of things. I am implementing a SOM solution with 38k records/observations using Kohonen SuperSOM following Self-Organising Maps for Customer Segmentation using R.
My data have no missing values but almost 60 columns many of them are dummyVars (I received this data in this format)
I have removed the ONE char Column (URL)
My Y column (as I understand it) is "shares" (How many times it was shared)
My data only consist of numerical data (dummyVars are of course 1 or 0)
I have Centered and Scaled my data (entire dataFrame)
As per the example I followed I dod convert the entire DF to a matrix
My problem is that my SOM takes ages to train even with multi core processing and my progress graph does not reach a nice flat"ish" plateau, it does come nicely down but still is very erratic, all my other graphs are extremely high in population and there are no nice clustering. I have even tried a 500 iteration with a 100x100 grid ;-(
I think /guess it is because of the huge amount of columns including mostly dummyVars e.g. dayOfWeek.Monday, dayOfWeek.Tuesday, category.LifeStile, category.Computers, etc.
What am I to do?
Should I convert the dummyVars back into another format, How and Why?
Please do not just give me a section of code as I would like to understand why I need to do What.
Thanx
I am currently attempting to implement a trading idea that I have been playing around with. It consists of 50+ securities and has a strategy very similar to this one. (Current package I am using is quantmod).
http://www.r-bloggers.com/backtesting-a-simple-stock-trading-strategy/
For those who aren't interested in clicking, it is a strategy that will look at the pass X days( in his case 200 ) and enter a position depending on the peak reached in the stock. I understand how to do this strategy for my idea, but I cannot grasp how to aggregate my data into one summary.
Is there a way I can consolidate the summary for all the positions I have entered into one larger portfolio summary and chart that against the S&P 500?
Any advice on where I can find resources or being lead to the information. I have looked at portfolio analysis package for R and I do not believe that will be much help to me.
Thank you in advance.
Edit: In the link, at the bottom, there are 3 indexes that are FTSE, N225, DJIA. Could i combine those 3 summaries to show the same output as below, BUT combined
FTSE:
Me Index
Cumulative Return 3.56248582 3.8404476
Annual Return 0.05667121 0.0589431
Annualized Sharpe Ratio 0.45907768 0.3298633
Win % 0.53216374 0.5239884
Annualized Volatility 0.12344579 0.1786895
Maximum Drawdown -0.39653398 -0.5256991
Max Length Drawdown 1633.00000 2960.0000
Could I get that same output but for the 3 securities data combined? Is there a effective way of doing that. Thank you so much. Happy holidays
It's a little unclear to me what you mean by "combine" in this case. If you want a single column representing the combined returns from all three exchanges as if they were a single unified market, that's really tricky, because the exchanges trade in different currencies (British pounds; U.S. dollars, Japanese Yen, etc.). The underlying analysis would have to be modified substantially to take into account fluctuating daily foreign exchange rates.
I suspect that this is NOT want you want. Rather, you are simply asking how to take three sequential two-column outputs and turn them into a single parallel six-column output.
If that is indeed what you want, then you need to rewrite the testStrategy() function shown near the bottom of the link. As it's currently written, that function takes three inputs: an index name myStock (with allowed values of FTSE, DJIA, or N225), and two integer values, nHold and nHigh. You would need to change it so that it instead accepts five inputs; e.g., myStockA, myStockB and myStockC, plus the two integer values already mentioned. Then each of the lines currently referring to myStock would have to be replicated three times. Finally, the two cbind() lines that you see at the bottom would have to be modified so that instead of merging the data together into only two columns, you include all six.
For a good intro tutorial on how to write and modify your own R functions, please see this. To understand how to use the cbind() function, which you will have to call with six rather than two inputs, please see this.
I'm struggling with how to best structure categorical data that's messy, and comes from a dataset I'll need to clean.
The Coding Scheme
I'm analyzing data from a university science course exam. We're looking at patterns in
student responses, and we developed a coding scheme to represent the kinds of things
students are doing in their answers. A subset of the coding scheme is shown below.
Note that within each major code (1, 2, 3) are nested non-unique sub-codes (a, b, ...).
What the Raw Data Looks Like
I've created an anonymized, raw subset of my actual data which you can view here.
Part of my problem is that those who coded the data noticed that some students displayed
multiple patterns. The coders' solution was to create enough columns (reason1, reason2,
...) to hold students with multiple patterns. That becomes important because the order
(reason1, reason2) is arbitrary--two students (like student 41 and student 42 in my
dataset) who correctly applied "dependency" should both register in an analysis, regardless of
whether 3a appears in the reason column or the reason2 column.
How Can I Best Structure Student Data?
Part of my problem is that in the raw data, not all students display the same
patterns, or the same number of them, in the same order. Some students may do just one
thing, others may do several. So, an abstracted representation of example students might
look like this:
Note in the example above that student002 and student003 both are coded as "1b", although I've deliberately shown the order as different to reflect the reality of my data.
My (Practical) Questions
Should I concatenate reason1, reason2, ... into one column?
How can I (re)code the reasons in R to reflect the multiplicity for some students?
Thanks
I realize this question is as much about good data conceptualization as it is about specific features of R, but I thought it would be appropriate to ask it here. If you feel it's inappropriate for me to ask the question, please let me know in the comments, and stackoverflow will automatically flood my inbox with sadface emoticons. If I haven't been specific enough, please let me know and I'll do my best to be clearer.
Make it "long":
library(reshape)
dnow <- read.csv("~/Downloads/catsample20100504.csv")
dnow <- melt(dnow, id.vars=c("Student", "instructor"))
dnow$variable <- NULL ## since ordering does not matter
subset(dnow, Student%in%c(41,42)) ## see the results
What to do next will depend on the kind of analysis you would like to do. But the long format is the useful for irregular data such as yours.
you should use ddply from plyr and split on all of the columns if you want to take into account the different reasons, if you want to ignore them don't use those columns in the split. You'll need to clean up some of the question marks and extra stuff first though.
x <- ddply(data, c("split_column1", "split_column3" etc),
summarize(result_df, stats you want from result_df))
What's the (bigger picture) question you're attempting to answer? Why is this information interesting to you?
Are you just trying to find patterns such as 'if the student does this, then they also likely do this'?
Something I'd consider if that's the case - split the data set into smaller random samples for your analysis to reduce the risk of false positives.
Interesting problem though!
First off, this may be the wrong Forum for this question, as it's pretty darn R+Bioconductor specific. Here's what I have:
library('GEOquery')
GDS = getGEO('GDS785')
cd4T = GDS2eSet(GDS)
cd4T <- cd4T[!fData(cd4T)$symbol == "",]
Now cd4T is an ExpressionSet object which wraps a big matrix with 19794 rows (probesets) and 15 columns (samples). The final line gets rid of all probesets that do not have corresponding gene symbols. Now the trouble is that most genes in this set are assigned to more than one probeset. You can see this by doing
gene_symbols = factor(fData(cd4T)$Gene.symbol)
length(gene_symbols)-length(levels(gene_symbols))
[1] 6897
So only 6897 of my 19794 probesets have unique probeset -> gene mappings. I'd like to somehow combine the expression levels of each probeset associated with each gene. I don't care much about the actual probe id for each probe. I'd like very much to end up with an ExpressionSet containing the merged information as all of my downstream analysis is designed to work with this class.
I think I can write some code that will do this by hand, and make a new expression set from scratch. However, I'm assuming this can't be a new problem and that code exists to do it, using a statistically sound method to combine the gene expression levels. I'm guessing there's a proper name for this also but my googles aren't showing up much of use. Can anyone help?
I'm not an expert, but from what I've seen over the years everyone has their own favorite way of combining probesets. The two methods that I've seen used the most on a large scale has been using only the probeset which has the largest variance across the expression matrix and the other being to take the mean of the probesets and creating a meta-probeset out of it. For smaller blocks of probesets I've seen people use more intensive methods involving looking at per-probeset plots to get a feel for what's going on ... generally what happens is that one probeset turns out to be the 'good' one and the rest aren't very good.
I haven't seen generalized code to do this - as an example we recently realized in my lab that a few of us have our own private functions to do this same thing.
The word you are looking for is 'nsFilter' in R genefilter package. This function assign two major things, it looks for only entrez gene ids, rest of the probesets will be filtered out. When an entrez id has multiple probesets, then the largest value will be retained and the others removed. Now you have unique entrez gene id mapped matrix. Hope this helps.