pandas and numpy quick-ref list index
HowTo
Reading the Notorious Excel files
df = pd.read_excel(filename,
skiprows=num_title_rows,
skip_footer=num_footer_rows)
# normal pd.DataFrame operations
select where col = ‘some-col’
# 1. create a Boolean mask
mask = df['col'] == 'some-col'
# 2. apply the mask to the DF
cursor = df[mask]
# or simpler all-in-once
cursor = df[df['col'] == 'some-col']
select where col contains sub-string ‘das’ or ‘der’
# 1. get col series
series = df['col'].str
# 2. make mask
mask = series.contains('das|der') # regexp supported!
# 3. apply mask to DF
cursor = df[mask]
Append A Column of Ones
In [4]: l1 = np.random.randint(0, 10, (3, 4))
In [5]: l1
Out[5]:
array([[5, 7, 2, 8],
[0, 0, 0, 7],
[0, 8, 6, 7]])
In [6]: np.concatenate([l1, np.ones((3, 1))], axis=1)
Out[6]:
array([[ 5., 7., 2., 8., 1.],
[ 0., 0., 0., 7., 1.],
[ 0., 8., 6., 7., 1.]])
In [7]: _