Clarify that .asnumeric() will convert 'enum' columns to underlying and show right approach

[exalate-issue-sync]

h1. +Add to Docs:+

If columns that are “enum” type want to be converted to “numeric” type, they should be converted to “character” first, then use “numeric”. Otherwise, the values may be converted to underlying factor values, not the expected mapped values.

Python Example:

{noformat}prostate["column"] = prostate["column"].ascharacter().asnumeric(){noformat}

R Example:

{noformat}prostate[, 2] <- as.character(prostate[, 2])
prostate[, 2] <- as.numeric(prostate[, 2]){noformat}

This behavior is similar to R datatables.

Sections to consider adding to:

[https://docs.h2o.ai/h2o/latest-stable/h2o-py/docs/frame.html?highlight=asnumeric#h2o.H2OFrame.asnumeric|https://docs.h2o.ai/h2o/latest-stable/h2o-py/docs/frame.html?highlight=asnumeric#h2o.H2OFrame.asnumeric|smart-link]

[https://docs.h2o.ai/h2o/latest-stable/h2o-docs/data-munging/change-column-type.html?highlight=asnumeric|https://docs.h2o.ai/h2o/latest-stable/h2o-docs/data-munging/change-column-type.html?highlight=asnumeric|smart-link]

[https://docs.h2o.ai/h2o/latest-stable/h2o-r/docs/reference/as.numeric.html|https://docs.h2o.ai/h2o/latest-stable/h2o-r/docs/reference/as.numeric.html|smart-link]

[https://docs.h2o.ai/h2o/latest-stable/h2o-r/docs/reference/h2o.asnumeric.html|https://docs.h2o.ai/h2o/latest-stable/h2o-r/docs/reference/h2o.asnumeric.html|smart-link]

h1. Background

User found that .asnumeric() may behave differently than expected. The new “numeric” values are based on the underlying values (not the mapped values).

{noformat}df1 = pd.DataFrame([[1.1, '1.1%'], [2, '2'], [3, '3']])
hframe1 = h2o.H2OFrame(df1, column_types=['real', 'enum'])
hframe1{noformat}

Output:

||0||1||
|1.1|1.1%|
|2|2|
|3|3|

{noformat}hframe1["1"] = hframe1["1"].gsub(pattern="%", replacement="")
hframe1["1"] = hframe1["1"].trim()
hframe1{noformat}

||0||1||
|1.1|1.1|
|2|2|
|3|3|

{noformat}hframe1.asnumeric(){noformat}

||0||1||
|1.1|{color:#6554c0}0{color}|
|2|1|
|3|2|

^ value 1.1 was converted to 0 (and other values become underlying values). This is similar to how R works.

Related issue: [https://h2oai.atlassian.net/browse/PUBDEV-8272|https://h2oai.atlassian.net/browse/PUBDEV-8272|smart-link]

[h2o-ops-ro]

JIRA Issue Details

Jira Issue: PUBDEV-8278
Assignee: hannah.tillman
Reporter: Neema Mashayekhi
State: Resolved
Fix Version: 3.34.0.4
Attachments: N/A
Development PRs: Available

[h2o-ops-ro]

Linked PRs from JIRA

#5822