data.table错误，导致R中的segfault [英] data.table bug, causing a segfault in R

问题描述

以下代码将我的 R 2.15.0 隔离，运行 data.table 1.8.9 。

The following code segfaults my R 2.15.0, running data.table 1.8.9.

library(data.table)
d = data.table(date = c(1,2,3,4,5), value = c(1,2,3,4,5))

# works as expected
d[-5][, mean(value), by = list(I(as.integer((date+1)/2)))]

# crashes R
d[-5, mean(value), by = list(I(as.integer((date+1)/2)))]

不同的输出：

d[-5][, value, by = list(I(as.integer((date+1)/2)))]
#    I value
# 1: 1     1
# 2: 1     2
# 3: 2     3
# 4: 2     4

d[-5, value, by = list(I(as.integer((date+1)/2)))]
#    I         value
# 1: 1 2.121996e-314
# 2: 1 2.470328e-323
# 3: 2 3.920509e-316
# 4: 2 2.470328e-323

更简单的命令会从评论中崩溃我的 R ：

Simpler command crashing my R from the comments:

d[-5, value, by = date]

正如里卡多指出的，它是负面索引和的组合造成的问题。

As Ricardo points out, it's the combination of negative indexing and by that creates the problem.

推荐答案

更新：这已经修复在v1.8.11。从新闻：

UPDATE: This has been fixed in v1.8.11. From NEWS :

在i中具有负索引的崩溃或不正确的聚合结果是固定的，＃2697 。
感谢Eduard Antonyan（eddi）的报告。已添加测试。

Crash or incorrect aggregate results with negative indexing in i is fixed, #2697. Thanks to Eduard Antonyan (eddi) for reporting. Tests added.

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