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ignoring_gravity
Asked: 2024-10-21 23:38:33 +0800 CST

根据映射替换数组中的所有值

  • 772

假设我有：

import pyarrow as pa

arr = pa.array([1, 3, 2, 2, 1, 3])

我想根据{1: 'one', 2: 'two', 3: 'three'}并最终替换值：

<pyarrow.lib.LargeStringArray object at 0x7f8dd0b3c820>
[
  "one",
  "three",
  "two",
  "two",
  "one",
  "three"
]

我可以通过 Polars 来实现这一点：

In [19]: pl.from_arrow(arr).replace_strict({1: 'one', 2: 'two', 3: 'three'}, return_dtype=pl.String).to_arrow()
Out[19]:
<pyarrow.lib.LargeStringArray object at 0x7f8dd0b3c820>
[
  "one",
  "three",
  "two",
  "two",
  "one",
  "three"
]

有没有办法只用 PyArrow 来完成它？

python

1 个回答

  1. Best Answer

    使用 pyarryow 计算模块中的函数可以实现你想要的功能

    下面是一个简单的例子

    $ cat /tmp/tomap.py
import pyarrow as pa

maps = {1: "one", 2: "two", 5: "five", 3: "three", 4: "four" }

numbersArr = pa.array([1, 3, 2, 2, 1, 3, 4, 5, 4, 1] )

idxs = pa.compute.index_in( numbersArr, pa.array(list(maps.keys())) ) #indices into

wordsArr = pa.compute.take( pa.array(list(maps.values())), idxs ) # lookup value at...

print(wordsArr)

$ python /tmp/tomap.py
[
  "one",
  "three",
  "two",
  "two",
  "one",
  "three",
  "four",
  "five",
  "four",
  "one"
]

    希望这对您有帮助，请查看https://arrow.apache.org/docs/python/compute.html了解详细信息

    • 3

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