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Martin Hope
sahuno
Asked: 2024-08-12 21:00:42 +0800 CST
  • 5

我想要cbind列表中的数据框，而不回收长度较短的项目

library(data.table)
library(dplyr)
library(rlist)

# Create a list of data.tables with unequal lengths
dt1 <- data.table(B = letters[1:3])
dt2 <- data.table( D = LETTERS[1:2])
dt3 <- data.table(F = letters[4:7])

# Put them in a list
dt_list <- list(dt1, dt2, dt3)

# cbind them
dplyr::bind_cols(dt_list)
rlist::list.cbind(dt_list)

更新：预期输出或类似内容

     B    D F
1    a    A d
2    b    B e
3    c <NA> f
4 <NA> <NA> g
Martin Hope
sahuno
Asked: 2024-08-05 07:29:27 +0800 CST
  • 9

paths应用 str.split("/") 函数后，如何选择列中列表的最后一项？

dataNpaths = pl.scan_csv("test_data/file*.csv", has_header=True, include_file_paths = "paths").collect()
dataNpaths.with_columns(pl.col("paths").str.split("/").alias("paths"))

>>> dataNpaths.with_columns(pl.col("paths").str.split("/").alias("paths"))
shape: (30, 5)
┌──────────┬──────────┬──────────┬──────────┬────────────────────────────┐
│ Column1  ┆ Column2  ┆ Column3  ┆ Column4  ┆ paths                      │
│ ---      ┆ ---      ┆ ---      ┆ ---      ┆ ---                        │
│ f64      ┆ f64      ┆ f64      ┆ f64      ┆ list[str]                  │
╞══════════╪══════════╪══════════╪══════════╪════════════════════════════╡
│ 0.603847 ┆ 0.509877 ┆ 0.091579 ┆ 0.43821  ┆ ["test_data", "file1.csv"] │
│ 0.572299 ┆ 0.817647 ┆ 0.087951 ┆ 0.397217 ┆ ["test_data", "file1.csv"] │
│ 0.886123 ┆ 0.159805 ┆ 0.766246 ┆ 0.083915 ┆ ["test_data", "file1.csv"] │
│ 0.142208 ┆ 0.413847 ┆ 0.043408 ┆ 0.147779 ┆ ["test_data", "file1.csv"] │
│ 0.105215 ┆ 0.924754 ┆ 0.309823 ┆ 0.724407 ┆ ["test_data", "file1.csv"] │
│ …        ┆ …        ┆ …        ┆ …        ┆ …                          │
│ 0.381675 ┆ 0.849887 ┆ 0.498281 ┆ 0.733085 ┆ ["test_data", "file3.csv"] │
│ 0.697427 ┆ 0.950464 ┆ 0.999596 ┆ 0.645253 ┆ ["test_data", "file3.csv"] │
│ 0.49979  ┆ 0.172414 ┆ 0.679287 ┆ 0.091804 ┆ ["test_data", "file3.csv"] │
│ 0.668585 ┆ 0.640259 ┆ 0.932463 ┆ 0.579558 ┆ ["test_data", "file3.csv"] │
│ 0.077462 ┆ 0.802565 ┆ 0.966791 ┆ 0.29297  ┆ ["test_data", "file3.csv"] │

但这两种方法都没有奏效

dataNpaths.with_columns(pl.col("paths").str.split("/")[-1].alias("paths"))
dataNpaths.with_columns(pl.col("paths").str.split("/",-1).alias("paths"))
python
Martin Hope
sahuno
Asked: 2023-09-01 20:29:51 +0800 CST
  • 6

我想使用/改变obs我在 data.table 中创建的列，但返回错误

Error in eval(jsub, SDenv, parent.frame()) : object 'obs' not found

请参阅示例数据的实现。

library(data.table)

set.seed(0)

dt <- data.table(
  index = sample(0:100, 10, replace=FALSE), 
  value = 1:100)

dt[, `:=`(obs = seq_along(index)-1, window = floor(obs/10))] #create an index of every observation and bin them