Using R, I would like to overlay some spatial points and polygons in order to assign to the points some attributes of the geographic regions I have taken into consideration. What I usually do is to use the command over of the sppackage. My problems is that I’m working with a large number of geo-referenced … Read more
Does f.seek(500000,0) go through all the first 499999 characters of the file before getting to the 500000th? In other words, is f.seek(n,0) of order O(n) or O(1)? Answer You need to be a bit more specific on what type of object f is. If f is a normal io module object for a file stored … Read more
I don’t understand how R handles the Python environment and Python version and keep getting the error Error: could not find a Python environment for /usr/bin/python. I installed Miniconda and created a conda environment in the shell: conda activate r-reticulate Then, in R, I try to install keras (same problem with package tensorflow): library(keras) reticulate::use_condaenv() … Read more
Using mtcars for reproduciblity (This is a row operation). I want to keep 3 values in a row based on their magnitude (so basically top 3 values would be having value, rest everything change to NA) I tried using pivot_longer converting to long then filtering but problem is I want to convert again to wide … Read more
i got some files with name start as eg_. and only each contains one single line eg_01.txt: @china:129.00 eg_02.txt @uk:219.98 eg_03.txt @USA:341.90 …… i am expecting to cat them in to a single line to send by URL like: @china:129.00@uk:219.98@USA:341.90 i use echo cat eg_* it give me the output look like a string, but … Read more
I’m writing a graphical URI handler for git:// links with bash and zenity, and I’m using a zenity ‘text-info’ dialog to show git’s clone output while it’s running, using FIFO piping. The script is about 90 lines long, so I won’t bother posting it here, but here’s the most important lines: git clone “$1” “$target” … Read more
What’s the best way to pass bash variables to a python script. I’d like to do something like the following: $cat test.sh #!/bin/bash foo=”hi” python -c ‘import test; test.printfoo($foo)’ $cat test.py #!/bin/python def printfoo(str): print str When I try running the bash script, I get a syntax error: File “<string>”, line 1 import test; test.printfoo($foo) … Read more
The following is the example I work on. require(lattice) data(barley) xyplot(yield ~ year | site, data = barley) I want to put different strip color for different sprips and font color is also different optimized with the backgroud color. For example: strip background colors = c(“black”, “green4”, “blue”, “red”, “purple”, “yellow”) font color = c(“white”, … Read more
I am using the following R code (that utilizes the Java parameter to increase memory as well): library(xlsx) options(java.parameters = “-Xmx1g”) library(XLConnect) NiVe <- read.xlsx(“version1.xlsx”,1) The version1.xlsx file is 13 MB in size. I get the following error: Error in .jcall(“RJavaTools”, “Ljava/lang/Object;”, “invokeMethod”, cl, : java.lang.OutOfMemoryError: Java heap space Can someone help? Answer Try to … Read more
I have a large matrix (2e6 x 3) which I have to write to a text file. dlmwrite takes about 230s to achieve this task. From your experience what is the fastest way to write a large matrix to a text file? Answer The following applies to MATLAB, but I suggest you try it in … Read more
