Reduce merge r In this article, I will explain how to perform join or merge on multiple data frames in R (more than two data frames). Is there any easy way to do it? 文章浏览阅读3. Merge two dataframes with repeated columns. My dataframes are named Cluster_1_N1, Cluster_1_N2, Cluster_1_N3 Cluster_2_N1 在R语言中，Reduce函数是一个非常实用的函数，用于对向量或列表进行累积计算。它可以将一个二元函数（接受两个参数的函数）应用于一个序列的元素上，将它们从左到右逐一组合，最终得到一个单一的输出值。这个输出值取决于所使用的二元函数和序列中的元素。 Reduce takes a binary function and a list of data items and successively applies the function to the list elements in a recursive fashion. tables and want to use do. 0. The main data-wrangling use of “split-apply-combine” is for “grouped summaries. , & Sohler, C. multiMerge elegantly avoids such bewildering code chunks by invoking Reduce upon a list of data frames. Modified 4 years, 5 months ago. Follow Para unir data. Explore and discover thousands of packages 文章浏览阅读5. Creamos un par de DF para usarlos en el ejemplo ```{r} Df1 = data. (The popularization of “split-apply-combine” as an organizing principle for data-wrangling I am aware that one can merge (join) two data. Reduce(function(x, y) merge(x, y), list(x, y, z)) id año edad salario 1 1995 25 1000 2 1996 24 1200 3 1997 23 1599 R PACKAGES. On Reduce(merge, DF_obj) should work. Note that the code is mainly taken from a related blog post in StackOverflow. frames with two column, all of them share the first column. Not much of a speed difference, though. To count the number of vectors that a 方法1：使用Base R合并多个数据框 假设 #merge all data frames together Reduce (function (x, y) merge (x, y, all = TRUE), df_list) id revenue expenses profit 1 1 34 22 12 2 2 36 26 10 3 3 40 NA NA 4 4 49 NA 14 5 5 43 31 12 6 6 NA 40 NA 7 7 NA 20 9. Merge 2 data table according to a slightly different column. names(x)))) [1] rn Aaa Xxx Yyy Rrr Ggg <0 rows> (or 0-length row. The resulting dataframe should look like this: Resulting Dataframe: The merge Function in R; Merge Data Frames by Row Names; Convert List to Data Frame; Row Bind Data in R; Column Bind Data in R; Join Data with dplyr Package; R Functions List (+ Examples) The R Programming Language . How to join 2 or more data frames. It adds to Map-Reduce a Merge phase that can efficiently merge data already partitioned and sorted (or hashed) by map and reduce modules. Merge two tables withe condition R. merge() y Reduce() by Raul Ortiz; Last updated about 9 years ago; Hide Comments (–) Share Hide Toolbars title: "Unir Data Frames II. concat()，可以方便的实现纵向合并；可是横向合并怎么处理呢？？方法一：嵌套函数方法df1. jusqu'au tableau N pour n'avoir au final qu'un seul 这会产生所需的结果(将各个数据帧合并为单个数据帧)，并在37秒内完成。 但是，在整个40K数据帧列表上运行Reduce()会花费大量的时间。我让它运行了5个小时以上，但它似乎没有完成。 R - Reduce function used for merging returns a list instead of a dataframe. Rd. X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17 X18 Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company The reduce() function from the purrr package can be used in conjunction with dplyr join functions to merge multiple data frames in a list based on a common column. Merge two dataframe and create new on with smaller values. 3 How to Drop X in Column names after Merge R reduce/combine columns in a data. complete, locationNames. I want to merge all the rows not separated by a value > -1 that are close to the min activity value. Here is my codes: I used merge: merge is a base R function whereas full_join is dplyr. Using reduce to Merge several csv files with more than one column as condition and different length. Reduce主要有两个参数：. This solution comes on the back of How to ddply() without sorting?, which deals with the issue of keeping order but in a split-apply-combine context:. , identifiers) that were used in the merging process. How to merge multiple data. The outcome data seems like the same. so merge data set looks like this . There is a classic approach how to simultaneously merge multiple data. N. We improve Map-Reduce into a new model called Map-Reduce-Merge. 21469989 and I am later going to merge them using column unit. id. call()`方法来实现批量合并，以及使用`tidyverse`包的`reduce()`函数。示例代码详细展示了如何合并本地文件夹中的数据以及直接给出 iLovePDF is an online service to work with PDF files completely free and easy to use. f. I'm using the below code to merge different data frames. Join data frame into one in r. 5952808 -2. Close ABT. cvs files using 3 columns in common in all the excel files. x 的下一个值作为第二个参数，. That's because I am later performing merging like this: MyMerge <- function(x, y){ df <- merge(x, y, by="unit", all. 注意，每个原始数据框中的 "id "值都包含在最终的数据框中。 You can use merge in Reduce: Reduce(merge, list(df, df1, df2, df3)) # ID YEAR MONTH DAY HOUR VALUE1 VALUE2 VALUE3 VALUE4 #1 A 2020 1 16 15 1 3 6 9 #2 B 2020 1 16 15 2 4 7 10 #3 C 2020 1 16 15 3 5 8 11 Share. Une conjuntos de datos por una o varias columnas o por los nombres de las filas con uniones SQL. y columns when merging or joining in r. 4. Table R:使用Reduce和merge合并四个以上的DT时出错 Bayesian linear regression using Merge and Reduce Description. frame method are:. We first call the package and store the data frames as data tables. Reduce with merge is very slow (16s) but if you replace merge with left_join then you have comparable speed as with the pipe (wee bit slower 1. 94202 #2007-01-05 The part-r-nnnnn files are generated after the reduce phase designated by 'r' in between. com/Rortizdu/140174 Merge Dimensional Reductions Source: R/dimreduc. groups (haven't been able to find MergedDF <- merge(DF1, DF2) %>% merge(DF3) As you mention in your post, this assumes that the column names are the same and that there's the same number of rows in each data frame you are merging. R. Ask Question Asked 6 years, 3 months ago. table function. Close #2007-01-03 11. 2 <- Reduce(merge,list(get(allSites))) The last of these three gives a data table that has columns from only the first data table in the allSites variable. Example > L [[1]] a b c d e 1 5 This seems to be easier with a for loop as the Reduce or reduce (purrr) at a time takes only two datasets, so we can't have more than two suffixes in the merge. 2 <- Reduce(merge,list(allSites)) combined. , Ickstadt, K. Viewed 137 times Part of R Language Collective 0 . 4 merging data in R. 03 How can I do that? I tried this but doesn't work: > l <- list(dat1, dat2, dat3) > Reduce(merge, lapply(l, function(x) data. Let’s replace our merge and Reduce solutions with data. . 6264538 1. To join more than two (multiple) R dataframes, then reduce() is used. merged<-merge(test, test) or 参数. I wonder whether I am using them in the correct way. 07456498 4 4 1. 0 Merging specific rows in R. file 1. states完全匹配的数据。 Aprende a unir data frames en R con la función merge(). , "code, food, isFruit" instead of "food, R 'merge' is changing data in the merging dataframes. Streaming statistical models via Merge & Reduce. table with the merge function or the [. Mth_TaT_Data <- Reduce(function(x,y) merge(x,y,by= "Order. Share. the idea is all about reducing down a collection of elements into a singular value given a state and the first value in the list a new state can be generated. Improve How can I prevent this and have merge(x, y) use the same column order of x and just insert the new variable (isFruit) as the third column (i. 49581 #2007-01-04 12. 9k次，点赞5次，收藏24次。批量处理表格，实现查找匹配stackoverflow原问题链接。假设我们有 >=3 个csv表格，使用pands. Geppert, L. ” The best introduction to this is Grolemund and Wickham’s R for Data Science, Chapter 5, where they are introducing data transformations through the tidyverse tool dplyr. You can use either the R base function or the reduce() function from the tidyverse package. 9s on average but not significant). 1836433 0. names = letters[1:3]) > a <- I have 13 csv files each with 315-320 observations of a total of 26 variables plus an id column that I would like to merge in R. For example: Reduce(intersect,list(a,b,c)) is the same as. frame Often you may want to reduce a list in R to a single value by iteratively applying a binary function. 3w次，点赞19次，收藏46次。本文介绍了如何在R中高效地合并多个数据框，包括按列合并和按行合并。提供了自定义函数和`do. International Journal of Data Science and The arguments of merge. y= TRUE) return(df) } data <- Reduce(MyMerge, tables) I need to merge these 5 data frames by POLY, STRA and Spp such that the final result looks like: For several data frames you can use Reduce: Reduce(merge, list(df1, df2, df3, df4, df5)) If there are any missing rows in any of the data frames all = TRUE may help: Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company What I want to merge/left_join 3 of them into this final data frame (not tibble): NA NA NA 0. frame. If you put all the data frames into a list, you can then use grep and cbind to get the data frames with the desired row names. frame using dplyr::bind_cols However this is not possibl as other have said, reduce is also often known as fold. The problem is, I would like to use the merge function with the argument all=T, and there seems to be nowhere to specify this in the higher-order Reduce function. For instance, reducing the vector 1:3 with the binary function + computes the sum ((1 + 2) + 3) from the left, and the same sum (1 + (2 + 3)) from the right. For instance, reducing a vector with list() from Conceptually though, Merge and Reduce is not an updating algorithm as it merges models based on a comparable amount of data along a tree structure to obtain a final model. "merge" in base R and "join" in plyr appear to use up all my memory effectively crashing my system. noT)) combined. Now the fact is if you have one reducer running, you will have an output file like part-r-00000. frame(x, rn = row. Table R:使用Reduce和merge合并四个以上的DT时出错 关注问题 社区首页 > 问答首页 > Data. 2. But to be able to merge by rownames, first we need to write them to a column. f is an associative operation like + or c(), the direction of reduction does not matter. combined. R CODER Inicio; Aprende R. The slowest is join_all from plyr R语言 -- 交并补：intersect、union、setdiff、Reduce多重操作 merge table in R. Fitting frequentist linear models using Merge and Reduce: mrregression: mrregression: Frequentist and Bayesian linear regression using Merge and Reduce. y with the names of the columns in the respective data frames. Then loop through the sequence of 'list. x = TRUE), list(x,y,z)) The full_join variant works perfectly, and looks a lot less scary than the accepted answer. The key arguments of base merge data. 商业数据分析师的 R 语言学习笔记,主要集中在数据清洗相关包的介绍，从数据导入(本地数据 数据库)到数据清洗，到固定报表输出的自动化流程。 在实际工作中,我常用reduce函数实现连续merge() We can use dplyr::full_join with purrr::reduce to merge multiple dataframes. R CODER Home; Learn R. R - reduce with merge and more than 2 suffixes (or: how to merge multiple dataframes and keep track of columns) 1. 97143 NA 23. Using ‘merge()’ from base R: The merge() function in base R helps us to combine two or more data frames based on common columns. 51178117 0. intersect((intersect(a,b),c) However, I don't think that construct will help you here as it will only return those elements that are common to all vectors. 8356286 -0. I get them in a list and want to combine them into one data. frames two by two, and so on, until there is only one remaining data. By default the column is called "rowname". 6k次，点赞3次，收藏7次。本文介绍了如何在Python中利用merge()函数结合reduce()函数来合并多个数据表。首先展示了创建数据表的过程，接着详细解释了merge()函数的用法，特别是'on'参数和'how'参数的含义。最后，通过实例演示了当需要合并多个数据表时，如何结合reduce()函数完成操作。 Bonjour, la fonction Reduce sert à faire du récursif sur des éléments deux à deux. merge. It is relevant to ask, if more efficient code can be written that provides the same results. 0 Merge Function in R. merge(df2,on='目标列的名称'). The criteria would be merging them by the column 'Date' (the column should have all the dates of all the merged dataframes, ordered by date). References. Fortunately this is easy to do by using the reduce() function from the purrr package in R, which is designed to perform I'm trying to use the Reduce function in R to use the merge function across multiple dataframes. Syntax: merged_df <- merge(x,y,by = "common_column",. The output, however, is somewhat disordered. table code. Viewed 124 times Part of R Language Collective 0 . This guide simplifies the process, ensuring you avoid common pitfa I need to merge a lot of dataframes with sequential names (df1, df2, df3, ) by the first column. It performs various types of joins such as inner join, left join, right join, and full join. x and . DimReduc. Merge dataframes but keep common column. Nested full_join with suffixes for more than 2 data. sites. I'm working with a dataframe and would like to merge two columns into one, if two of the cells have the same value. frame(x2 = c(3,6,9), row. Improve this answer. So I'd like: In this article, I will explain how to perform join or merge on multiple data frames in R (more than two data frames). 1",all=TRUE), list(n_Cases,n_Auth_Cases data. Now, we want to reduce those data frames by left_joining them two-by-two which is not based on common column/columns; in our case, that would have been column a. This will also automatically eliminate any duplicate columns (i. 78213630 3 3 -0. Initialize an output dataset with the first list element. Join datasets by one or multiple columns or by row names with the different database joins. Ask Question Asked 4 years, 5 months ago. However, I wish that instead of count, I could use original filename from variable files as a second column. 91897737 2 2 0. and try. 8s) (~10x faster in my case- conditional to your data of course etc. Explora y descubre miles de Direction. Merge PDF, split PDF, compress PDF, office to PDF, PDF to JPG and more! 文章浏览阅读2. Example load test data frame. Modified 6 years, 3 months ago. this is then processed with the second item, the output of that with the thirduntil the end of the iterable is reached. Com as funções base do R, uma forma de fazer um merge direto dos três é combinando a função Reduce com o merge: resultado <- Reduce(function(x,y) {merge(x,y)}, list(df1, df2, df3)) resultado id y z x 1 1 -0. We also demonstrate that this new model can express relational algebra operators as well as implement several join algorithms. If the number of reducers are 2 then you're going to have part-r Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog The pipe option and reduce with join_left are much faster (1. x. I attempted this using the following code: filenames<-list. I am trying to create one data frame from 87 . I has the advantage that the name of the list element is added as a new first column, named . If the column names are different in the two data frames to merge, we can specify by. noWind, locationNames. DATE PRICE1 CLOSE1 PRICE2 CLOSE2. R语言-快速对多个变量取交集，最终用到了Reduce函数。本文将专门介绍Reduce函数地绝妙之处，让你的代码简短而强大。在R语言数据处理的过程中，我们经常需要对不同类型的数据进行聚合、累积或归约操作。Reduce函数是R语言中一个强大的工具，能够将一个序列的元素逐步减少为单个结果。 Here’s how to create and merge df_list together with base R and Reduce(): df_list <-list for (i in 1: 3) {df_list [[i]] <-create_df (i) #Yes, you could also use lapply(1:3, create_df), but I went for maximum ugliness} Reduce (function (x, y) merge (x, y, by = "A", all = TRUE), df_list) Hideous, right?! Behold the glory of the tidyverse: Grouped summaries in the tidyverse. We will see how to perform the join operation on two or multiple DataFrames in R using merge() function. y. Fortunately this is easy to do by using the reduce() function from the purrr R Pubs by RStudio. In addition, a list of data frames is often the output of tapply, in which case replace the whole shebang with ddply. Date Price Close PRICE CLOSE I want something like. Viewed 287 times Part of R Language Collective 2 . I am looking for an efficient (both computer resource wise and learning/implementation wise) method to merge two larger (size>1 million / 300 KB RData file) data frames. df' and do a sequential merge with the 'res' and the next element of list. If there are more than two Here’s how to create and merge df_list together with base R and Reduce(): df_list <- list () for ( i in 1 : 3 ) { df_list [[ i ]] <- create_df ( i ) #Yes, you could also use lapply(1:3, create_df), but I went for maximum ugliness } Discover how to easily combine multiple dataframe objects in R using `Purrr` and `reduce`. Viewed 506 times Part of R Language Collective 0 . frames in a list. frame(x3 = c(1,2,3), row. 列表或原子向量。. How to merge two data frames. 2 <- Reduce(merge,list(locationNames. And keep the first value of start and last value of end for the merged rows and mean computed on the selected rows. Merge two or more dimensional reduction together # S3 method for DimReduc merge (x = NULL, Dimensional reduction object, validity, and interaction methods CreateDimReducObject(), DimReduc-class R： Reduce 累积迭代函数 R语言作为数据的工具还是很受欢迎的，因为它内置了很多好用的函数，如果没有内置的函数也会第三方的包可以用，这使得R对初学者来说很友善，学习成本不高。做数据处理有时候需要使用循环，在R中有好多函数可以用来替代循环，如 Merging multiple data frames in R is anything but straightforward and usually involves confusing loop structures. I have multiple data. In addition, we ask the question if we can use better readable syntax than above?. merge() y Reduce() by Raul Ortiz; Last updated about 9 years ago; Hide Comments (–) Share Hide Toolbars 文章浏览阅读506次。本文详细介绍了R语言中merge函数用于连接多个dataframe数据集的方法，包括迭代内连接和全连接，以及如何使用Reduce函数嵌套merge函数实现多个数据集的内连接。文中通过实例演示了merge函数的语法和操作，强调了默认通过公共列名合并数据集的 R Merge using Reduce Function duplicate columns. mrbayes is used to conduct Bayesian linear regression on very large data sets using Merge and Reduce as described in Geppert et al. names) r; dataframe; Share. How to merge two dataframes based on range value of one table. tibble::rownames_to_column does that. ) ‘x’ and ‘y’ are the data frames that you want to If I try to merge them based by date they do get merge but the columns have retained their old names and I want to rename them in a loop. Reduce(function(dtf1, dtf2) merge(dtf1, dtf2, by = "i", all. x= TRUE, all. If you really needed merge and not just rbind, you could first merge them two by two (1 and 2, 3 and 4, 5 and 6, etc. The main types of merge operations are: Inner Join (all = FALSE, default): An inner join returns only the rows with matching values in the specified columns from both data frames. ). Si ta liste L2 contient N data. ## set up the data > x <- data. I suspect there is For my money, the plyr package's ldply is the by way to do this. (2020). While there is a ready-made function join_all() for this in the plyr package, we will see shortly how to solve this task We will see how to perform the join operation on two or multiple DataFrames in R using merge() function. Sign in Register Unir Data Frames II. I'm trying to merge multiple dataframes according to their names. I tried merge and reduce. merge() y Reduce()" author: "Raúl Ortiz" date: "Monday, May 11, 2015" output: pdf_document---# Mediante el presente documento, veremos unir data. Use dataframe name as suffix when joining several data frames. frames with Reduce and get an ordered output? 1. Merging data frames with a non-unique column. 使用R中merge()函数合并数据 在R中可以使用merge()函数去合并数据框，其强大之处在于在两个不同的数据框中标识共同的列或行。如何使用merge()获取数据集中交叉部分 merge()最简单的形式为获取两个不同数据框中交叉部分。举例，获取cold. Alternatives include do. 9 r programming --- merge function returns column names with . frames. However, if I have say 10, data. The by argument can also be specified by Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company In R, the merge() function supports several types of merge operations that determine how data frames are combined based on the specified columns. names = letters[1:3]) > y <- data. The function also features a set of auxiliary parameters that are passed on to merge. Merge list of dataframe in R. here's reduce being used to find the length of any Direction. Close ABBV. ), then merge the resulting data. call to merge them all together, As an alternative to Reduce and merge:. Ask Question Asked 9 years, 6 months ago. 貌似是能解决问题，如果有4个向量呢？这个时候就要用到Reduce函数了。. Using the tidyverse function is the best approach as it runs faster than the R-based approach. Modified 9 years, 6 months ago. 1. I will need second eye to make sure I am not doing it wrong. Modified 6 years, 6 months ago. You can use Reduce with merge: out <- Reduce(merge, mget(ls(pattern = "price_"))) out # AAPL. f 返回包含在 done() 中的值 R merge reodering rows. 29 Avoiding and renaming . frame(x1 = c(2,4,6), row. x, y - the 2 data frames to be merged; by - names of the columns to merge on. 对于 reduce() ，一个 2 参数函数。 该函数将传递累积值作为第一个参数，"next" 值作为第二个参数。 对于 reduce2() ，一个 3 参数函数。 该函数将传递累加值作为第一个参数，. 使用. states和large. Related. In other cases, the direction has important consequences on the reduced value. R PACKAGES. df R - reduce with merge and more than 2 suffixes (or: how to merge multiple dataframes and keep track of columns) 1. f：代表所有执行的操作函数，例如：取交集函数intersect; x：一个列表，每个元素代表操作函数的参数; 例 The accepted answer proposes a manual way to keep order when using merge, which works most of the times but requires unnecessary manual work. names = letters[1:3]) > z <- data. frames en R existe la función merge que con todas sus opciones hace que esto sea una tarea fácil, sin embargo, se vuelve una tarea aburrida y repetitiva cuando se tienen muchos data. data. frames con el comando merge(). table’s solution to the above problem. x and by. Merge multiple dataframes with Reduce() and list() Hot Network Questions I would like to merge all dataframes in a single dataframe, without losing rows and placing nan where there are no things to merge. merge(df3,on='目标列的名称')优点：简单易理解。 data. test. Data. There are different join types including inner join, left join, right join, and outer join. Reduce(function(x, y) merge(x, y), list(x, y, z)) id year age wage 1 1995 25 1000 2 1996 24 1200 3 1997 23 1599. mrbayes: mrregression: Frequentist and Bayesian linear regression using Merge and Reduce. Package rstan needs to be installed. mrfrequentist: mrregression: Frequentist and Bayesian linear regression using Merge . 23714 NA 23. When . nobs. Improve Learn how to merge data in R with merge() function. 02 0. Unfortunately (unlike lapply() etc. Using the A more useful example would be joining multiple data frames with the same ids but different other columns. Ask Question Asked 6 years, 6 months ago. Suffixes when merging more than two data frames with full_join. 38984324 0. 62124058 0. e. This came up on the plyr mailing list a while back (raised by @kohske no Puedes copiar el script en el enlace:http://rpubs. frames para unir, puesto que la función merge solo permite la unión de dos a la vez, véase la definición de los argumentos y la ayuda de dicha función. Here, we created a vector of suffixes ('sfx'). How to merge data frame with same column names. Comment. If I use the code below (assuming 3 dataframes), it runs correctly: merged_df <- Often you may want to reduce a list in R to a single value by iteratively applying a binary function. frame alors le Reduce permet ici de 'merger' deux à deux les tableaux : tu commences à lier le tableau 1 et 2, puis le tableau joint avec le tableau 3, puis la jointure des tableaux avec le tableau 4, etc. For instance, reducing a vector By using the merge function and its optional parameters: Inner join: merge(df1, df2) will work for these examples because R automatically joins the frames by common variable names, but you would most likely want to specify merge(df1, df2, by = "CustomerId") to make sure that you were matching on only the fields you desired. call("rbind", mylist) or lattice's make. ) Reduce doesn't have a argument for passing additional named arguments to a function, so Reduce(merge, DF_obj, by=common_variable) doesn't R merge not duplicating columns even when some row differ between both dataframes. Join dataframe to vector [r] 上述代码中的merge函数将数据表A和B按照ID列进行连接，并将结果存储在数据表C中。如果我们有多个数据表需要连接，我们可以使用自定义函数和Reduce函数来实现次性性的多表连接。然后，使用Reduce函数将列表中的数据表依次应用于join_tables函数，按照ID列进行连接操作，并将结果存储在数据表C中。 文章浏览阅读418次，点赞4次，收藏6次。R语言-快速对多个变量取交集，最终用到了Reduce函数。本文将专门介绍Reduce函数地绝妙之处，让你的代码简短而强大。在R语言数据处理的过程中，我们经常需要对不同类型的数据进行聚合、累积或归约操作。Reduce函数是R语言中一个强大的工具，能够将一个序列 R Pubs by RStudio. y 的下一个值作为第三个参数。 如果 . , Munteanu, A. cnhnbjd tflydcm dgqktj ugdf fybeq tzkrw eoz vttuph jdelu xfny djmrio upnyu vcmjwi muxlt xeofku