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+--- Thread: .loc[row_indexer,col_indexer]...Help! (/thread-29099.html)
.loc[row_indexer,col_indexer]...Help! - Kromm - Aug-18-2020
Hello, guys.
Really new in the forum, as well as in Python.
I' m trying to work on a project and fell on this
:Error:***[u]C:\Users\kostas\Anaconda3\lib\site-packages\ipykernel_launcher.py:8: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy[/u]****sse={}
tx_recency = tx_user[['Recency']]
for k in range(1, 10):
kmeans = KMeans(n_clusters=k, max_iter=1000).fit(tx_recency)
tx_recency["clusters"] = kmeans.labels_
sse[k] = kmeans.inertia_
plt.figure()
plt.plot(list(sse.keys()), list(sse.values()))
plt.xlabel("Number of cluster")
plt.show()
RE: .loc[row_indexer,col_indexer]...Help! - carlhyde - Apr-13-2021
The first thing you should understand is that SettingWithCopyWarning is a warning, and not an error. The real problem behind the warning is that it is generally difficult to predict whether a view or a copy is returned. In most cases, the warning was raised because you have chained two indexing operations together. The SettingWithCopyWarning was created to flag "chained assignment" operations. This is made easier to spot because you might be used [] (square brackets) twice, but the same would be true if you used other access methods such as .loc[] , .iloc[] and so on.
Moreover, you can change the behaviour of SettingWithCopyWarning warning using pd.options.mode.chained_assignment with three option "None/raise"/"warn".