Python notes

panda_tips

1. Show installed versions

pd.__version__
# also show dependencies
pd.show_versions()

2. Create an example DataFrame

pd.DataFrame({'col one':[100, 200], 'col two':[300, 400]})
pd.DataFrame(np.random.rand(4, 8))
pd.DataFrame(np.random.rand(4, 8), columns=list('abcdefgh'))

3. Rename columns

df = df.rename({'col one':'col_1', 'col two':'col_2'}, axis='columns')
# if you want to rename all columns, use:
df.columns = ['col_one', 'col_two']
df.columns = df.columns.str.replace(' ', '_')
df.columns = df.columns.str.replace('_', '-')
df = df.add_prefix('Oo_')
df = df.add_suffix('_oO')

4. Reverse row records

df = df.loc[::-1]
# reset index after reversing the row records:
df = df.reset_index(drop=True)

5. Reverse column order

df = drinks.loc[:, ::-1]

6. Select columns by data type

df.select_dtypes(include='number').head()
df.select_dtypes(include=['number', 'object', 'category', 'datetime']).head()
df.select_dtypes(exclude='number').head()

7. Convert strings to numbers

df = df.apply(pd.to_numeric, errors='coerce').fillna(0)
df