These examples demonstrate methods of formatting data and deriving columns.

import pandas as pd
import oml

# Create a shopping cart data set.
shopping_cart = pd.DataFrame({
  'Item_name': ['paper_towel', 'ground_pork', 'tofu', 'eggs',
                'pork_loin', 'whole_milk', 'egg_custard'],
  'Item_type': ['grocery', 'meat', 'grocery', 'dairy', 'meat',
                'dairy', 'bakery'],
  'Quantity': [1, 2.6, 4, 1, 1.9, 1, 1],
  'Unit_price': [1.19, 2.79, 0.99, 2.49, 3.19, 2.5, 3.99]
  })
oml_cart = oml.push(shopping_cart)
oml_cart

# Add a column 'Price' multiplying 'Quantity' with 'Unit_price',
# rounded to 2 decimal places.
price = oml_cart['Quantity']*(oml_cart['Unit_price'])
type(price)
price
oml_cart = oml_cart.concat({'Price': price.round(2)})

# Count the pattern 'egg' in the 'Item_name' column.
egg_pattern = oml_cart['Item_name'].count_pattern('egg')
type(egg_pattern)
oml_cart.concat({'Egg_pattern': egg_pattern})

# Find the start index of substring 'pork' in the 'Item_name' column.
pork_startInd = oml_cart['Item_name'].find('pork')
type(pork_startInd)
oml_cart.concat({'Pork_startInd': pork_startInd})

# Check whether items are of grocery category.
is_grocery=oml_cart['Item_type']=='grocery'
type(is_grocery)
oml_cart.concat({'Is_grocery': is_grocery})

# Calculate the length of item names.
name_length=oml_cart['Item_name'].len()
type(name_length)
oml_cart.concat({'Name_length': name_length})

# Get the ceiling, floor, exponential, logarithm and square root
# of the 'Price' column.
oml_cart['Price'].ceil()
oml_cart['Price'].floor()
oml_cart['Price'].exp()
oml_cart['Price'].log()
oml_cart['Price'].sqrt()

Listing for This Example

>>> import pandas as pd
>>> import oml
>>> 
>>> # Create a shopping cart data set.
... shopping_cart = pd.DataFrame({
...   'Item_name': ['paper_towel', 'ground_pork', 'tofu', 'eggs',
...                 'pork_loin', 'whole_milk', 'egg_custard'],
...   'Item_type': ['grocery', 'meat', 'grocery', 'dairy', 'meat',
...                 'dairy', 'bakery'],
...   'Quantity': [1, 2.6, 4, 1, 1.9, 1, 1],
...   'Unit_price': [1.19, 2.79, 0.99, 2.49, 3.19, 2.5, 3.99]
...   })
>>> oml_cart = oml.push(shopping_cart)
>>> oml_cart
     Item_name Item_type  Quantity  Unit_price
0  paper_towel   grocery       1.0        1.19
1  ground_pork      meat       2.6        2.79
2         tofu   grocery       4.0        0.99
3         eggs     dairy       1.0        2.49
4    pork_loin      meat       1.9        3.19
5   whole_milk     dairy       1.0        2.50
6  egg_custard    bakery       1.0        3.99
>>> 
>>> # Add a column 'Price' multiplying 'Quantity' with 'Unit_price',
... # rounded to 2 decimal places.
... price = oml_cart['Quantity']*(oml_cart['Unit_price'])
>>> type(price)
<class 'oml.core.float.Float'>
>>> price
[1.19, 7.254, 3.96, 2.49, 6.061, 2.5, 3.99]
>>> oml_cart = oml_cart.concat({'Price': price.round(2)})
>>> 
>>> # Count the pattern 'egg' in the 'Item_name' column.
... egg_pattern = oml_cart['Item_name'].count_pattern('egg')
>>> type(egg_pattern)
<class 'oml.core.float.Float'>
>>> oml_cart.concat({'Egg_pattern': egg_pattern})
     Item_name Item_type  Quantity  Unit_price  Price  Egg_pattern
0  paper_towel   grocery       1.0        1.19   1.19            0
1  ground_pork      meat       2.6        2.79   7.25            0
2         tofu   grocery       4.0        0.99   3.96            0
3         eggs     dairy       1.0        2.49   2.49            1
4    pork_loin      meat       1.9        3.19   6.06            0
5   whole_milk     dairy       1.0        2.50   2.50            0
6  egg_custard    bakery       1.0        3.99   3.99            1
>>> 
>>> # Find the start index of substring 'pork' in the 'Item_name' column.
... pork_startInd = oml_cart['Item_name'].find('pork')
>>> type(pork_startInd)
<class 'oml.core.float.Float'>
>>> oml_cart.concat({'Pork_startInd': pork_startInd})
     Item_name Item_type  Quantity  Unit_price  Price  Pork_startInd
0  paper_towel   grocery       1.0        1.19   1.19             -1
1  ground_pork      meat       2.6        2.79   7.25              7
2         tofu   grocery       4.0        0.99   3.96             -1
3         eggs     dairy       1.0        2.49   2.49             -1
4    pork_loin      meat       1.9        3.19   6.06              0
5   whole_milk     dairy       1.0        2.50   2.50             -1
6  egg_custard    bakery       1.0        3.99   3.99             -1
>>> 
>>> # Check whether items are of grocery category.
... is_grocery=oml_cart['Item_type']=='grocery'
>>> type(is_grocery)
<class 'oml.core.boolean.Boolean'>
>>> oml_cart.concat({'Is_grocery': is_grocery})
     Item_name Item_type  Quantity  Unit_price  Price  Is_grocery
0  paper_towel   grocery       1.0        1.19   1.19        True
1  ground_pork      meat       2.6        2.79   7.25       False
2         tofu   grocery       4.0        0.99   3.96        True
3         eggs     dairy       1.0        2.49   2.49       False
4    pork_loin      meat       1.9        3.19   6.06       False
5   whole_milk     dairy       1.0        2.50   2.50       False
6  egg_custard    bakery       1.0        3.99   3.99       False
>>> 
>>> # Calculate the length of item names.
... name_length=oml_cart['Item_name'].len()
>>> type(name_length)
<class 'oml.core.float.Float'>
>>> oml_cart.concat({'Name_length': name_length})
     Item_name Item_type  Quantity  Unit_price  Price  Name_length
0  paper_towel   grocery       1.0        1.19   1.19           11
1  ground_pork      meat       2.6        2.79   7.25           11
2         tofu   grocery       4.0        0.99   3.96            4
3         eggs     dairy       1.0        2.49   2.49            4
4    pork_loin      meat       1.9        3.19   6.06            9
5   whole_milk     dairy       1.0        2.50   2.50           10
6  egg_custard    bakery       1.0        3.99   3.99           11
>>> 
>>> # Get the ceiling, floor, exponential, logarithm and square root
... # of the 'Price' column.
... oml_cart['Price'].ceil()
[2, 8, 4, 3, 7, 3, 4]
>>> oml_cart['Price'].floor()
[1, 7, 3, 2, 6, 2, 3]
>>> oml_cart['Price'].exp()
[3.2870812073831184, 1408.1048482046956, 52.45732594909905, 12.061276120444719, 428.37543685928694, 12.182493960703473, 54.05488936332659]
>>> oml_cart['Price'].log()
[0.173953307123438, 1.9810014688665833, 1.3762440252663892, 0.9122827104766162, 1.801709800081223, 0.9162907318741551, 1.3837912309017721]
>>> oml_cart['Price'].sqrt()
[1.0908712114635715, 2.692582403567252, 1.98997487421324, 1.57797338380595, 2.4617067250182343, 1.5811388300841898, 1.997498435543818]