merge

问题 According to the bit twiddling hacks website, the operation unsigned int a; // value to merge in non-masked bits unsigned int b; // value to merge in masked bits unsigned int mask; // 1 where bits from b should be selected; 0 where from a. unsigned int r; // result of (a & ~mask) | (b & mask) goes here r = a ^ ((a ^ b) & mask); allows to merge two bit sequences a and b according to a mask. I was wondering: Whether this operation had a specific/usual name? Whether specific assembly instruction

问题 According to the bit twiddling hacks website, the operation unsigned int a; // value to merge in non-masked bits unsigned int b; // value to merge in masked bits unsigned int mask; // 1 where bits from b should be selected; 0 where from a. unsigned int r; // result of (a & ~mask) | (b & mask) goes here r = a ^ ((a ^ b) & mask); allows to merge two bit sequences a and b according to a mask. I was wondering: Whether this operation had a specific/usual name? Whether specific assembly instruction

问题 I have dozens of data frames in the global environment. I want to merge all of them without typing the names of all of them. How do I do this? 回答1: Following @Osssan's comments, and assuming that you want to merge everything in your global workspace, Get the names of the objects and then retrieve the objects themselves into a list: DF_obj <- lapply(ls(), get) If you want to merge on all common variables (e.g. if all variable names are unique except the one(s) you want to merge on), then just

问题 I have dozens of data frames in the global environment. I want to merge all of them without typing the names of all of them. How do I do this? 回答1: Following @Osssan's comments, and assuming that you want to merge everything in your global workspace, Get the names of the objects and then retrieve the objects themselves into a list: DF_obj <- lapply(ls(), get) If you want to merge on all common variables (e.g. if all variable names are unique except the one(s) you want to merge on), then just

问题 I am having 2 data frames in the below format: dt1 id col1 col2 col3 col4 ___ ____ ____ _____ _____ 1 2 3 1 2 2 3 4 1 1 3 1 1 1 1 4 1 2 1 2 5 1 1 1 1 6 1 2 1 2 dt2 id col1 col2 col3 col4 ___ ____ ____ _____ _____ 1 1 3 1 2 2 3 4 1 0 4 1 1 1 1 6 1 2 1 2 9 2 1 1 1 12 1 2 1 2 and I want to aggregate and combine these two data frames by the id and the resulting dataframe like dt3 id col1 col2 col3 col4 ___ ____ ____ _____ _____ 1 3 6 2 4 2 6 8 2 1 3 1 1 1 1 4 2 3 2 3 5 1 1 1 1 6 2 4 2 4 9 2 1 1 1

问题 This question already has answers here : Geographic / geospatial distance between 2 lists of lat/lon points (coordinates) (3 answers) Closed 4 years ago . My question is similar to Merging two data frames, both with coordinates based on the closest location. I would like to merge two dataframes in R by latitude and longitude: Dataframe 1 structure(list(lat = c(54L, 55L, 51L, 54L, 53L, 50L, 47L, 51L, 49L, 54L), lon = c(14L, 8L, 15L, 7L, 6L, 5L, 13L, 5L, 13L, 11L ), PPP2000_40 = c(4606, 6575,

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 10 months ago . Improve this question I am interesting in this process: First I'd like to make any in my development branch , than it should be pushed to Test (master) branch and, therefore, to production . For me the process: init commit then, make prod branch from master init commit then

问题 I have more than 10000 csv files in a folder and I'm trying to merge them by line using awk but if I run this command: printf '%s\n' *.csv | xargs cat | awk 'FNR==1 && NR!=1{next;}{print}' *.csv > master.csv I get the following errors: /usr/bin/awk: Argument list too long and printf: write error: Broken pipe 回答1: With the printf and xargs parts, you are sending the contents of the csv files into awk, but you also provide the filenames to awk. Pick one or the other: I'd suggest: { printf '%s\n

问题 It seems that merge causes columns of a data frame to lose their attributes: attr(mtcars$mpg, "units") <- "miles.per.gallon" new.df <- data.frame(gear=3:5, my.opinion=c("not enough", "just right", "too many")) merged.df <- merge(new.df, mtcars) attr(merged.df$mpg, "units") returns NULL . Is there a way to get merge to preserve attributes of columns? (A workaround would be to query the attributes of each column of each data frame before the merge, and then to re-assign them after the merge.

问题 I have a project, DemoA that was built off of a git repository, Project1. Unfortunately, DemoA started as simply a copy of the files from Project1, before itself turning into an actual long-term project. I would now like to make Project1 a submodule of DemoA, but - more importantly - want to merge in the changes done on the code derived from Project1, in DemoA. I have done a subtree split on DemoA to create a branch P1, which has all the changes done to the Project1 codebase in DemoA. I have