Errata

In chapter 6 (early online version of the book --> no page number...) , I think the regular expression is not correct in this bloc of code :

# Transform features from string to numeric
for i in ["term","int_rate","emp_length","revol_util"]:
data.loc[:,i] = \
data.loc[:,i].apply(lambda x: re.sub("[^0-9]", "", str(x)))
data.loc[:,i] = pd.to_numeric(data.loc[:,i])

If I'm not wrong (I checked this with R, not Python), with this approach, you are removing the decimal separators (points).
The consequence is minor for the variable "int_rate" because there is always 2 numbers after the points (the % are just multiplicated by 100).
But for "revol_util" you have for example 19% that will become 19 while 2.10% will become 210.

The point should be included in the brackets in the regex. With R syntax this would be (sorry I'm not certain of the Python syntax) :

txt2num <- c("term","int_rate","emp_length","revol_util")
for (i in txt2num) {
d[,i] <- as.numeric(gsub("[^0-9\\.]", "", d[,i]))
}

Note also that with this approach, in the variable " emp_length" the category "< 1 year" and "1 year" will both be transformed into the numeric value "1". Maybe it would be more appropriate to transform "< 1 year" into "0.5" to keep these value separated.

The consequence of this is probably minor for the demonstration of the technique in this chapter.
Thanks for the interesting book by the way...

Note from the Author or Editor:
You are right. The percentages are treated inconsistently for "int_rate" and "revol_util". But, all the features are transformed into numeric and then scaled, so the features (after performing scaling) are the exact same. We will keep the code as is for now, but we will note this for any substantial future revisions we make to this notebook. Thanks!

$ git lfs pull
instruction doe not exist

"(base) ~ >git lfs pull
git: 'lfs' is not a git command. See 'git --help'.

The most similar command is
log

Note from the Author or Editor:
Please add a "$pip install git-lfs" command before "$git lfs install".

The new code on page 28 should read:
$ git clone https://github.com/aapatel09/handson-unsupervised-learning.git
$ pip install git-lfs
$ git lfs install
$ git lfs pull

sais

$ activate unsupervisedLearning

should say

$ conda activate unsupervisedLearning

Note from the Author or Editor:
current:

$ activate unsupervisedLearning

should be:

$ conda activate unsupervisedLearning

[on page 28.]

"using confusion matrix would be useful" probably want to mean
"using confusion matrix would not be useful"

Note from the Author or Editor:
Given that our credit card transactions dataset is highly imbalanced, using the confusion matrix would be meaningful.

NEEDS TO BE THE FOLLOWING:
Given that our credit card transactions dataset is highly imbalanced, using the confusion matrix would not be meaningful.

denominator (true positive / false positive)
should be
(true positive / false negative)

Note from the Author or Editor:
Recall = True Positives / (True Positives + False Positives)

SHOULD BE:

Recall = True Positives / (True Positives + False Negatives)