I just can't figure out what "==" means at the second line:
- It is not a test, there is no if statement...
- It is not a variable declaration...
I've never seen this before, the thing is data.ctage==cat
is a pandas Series and not a test...
for cat in data["categ"].unique():
subset = data[data.categ == cat] # Création du sous-échantillon
print("-"*20)
print('Catégorie : ' + cat)
print("moyenne:\n",subset['montant'].mean())
print("mediane:\n",subset['montant'].median())
print("mode:\n",subset['montant'].mode())
print("VAR:\n",subset['montant'].var())
print("EC:\n",subset['montant'].std())
plt.figure(figsize=(5,5))
subset["montant"].hist(bins=30) # Crée l'histogramme
plt.show() # Affiche l'histogramme
It is testing each element of data.categ
for equality with cat
. That produces a vector of True/False values. This is passed as in indexer to data[]
, which returns the rows from data
that correspond to the True values in the vector.
To summarize, the whole expression returns the subset of rows from data
where the value of data.categ
equals cat
.
(Seems possible the whole operation could be done more elegantly using data.groupBy('categ').apply(someFunc)
.)