小能豆

Extracting tuples from a list in Pandas Dataframe

py

I have a dataframe with 12 column. I would like to extract the rows of a column depending on the values of another column.

Sample of my dataframe

order_id    order_type   order_items
45           Lunch       [('Burger', 5), ('Fries', 6)]
12           Dinner      [('Shrimp', 10), ('Fish&Chips', 7)]
44           Lunch       [('Salad', 9), ('Steak', 9)]
23           Breakfast   [('Coffee', 2), ('Eggs', 3)]

I would like to extract the breakfast, lunch and dinner menu by extracting the first item of each tuple. and extract the number of orders from the next item in the tuple.

Each item is type string according to this line of code

print(type(df['order_items'][0]))
>> <class 'str'>

I tried to apply a filter to extract the breakfast menu:

BreakfastLst=df.loc[df['order_type'] == 'Breakfast']['order_items']

but the output looks like this, and I can’t use a for loop to iterate through sublists and access the tuples.

2                           [('Coffee', 4), ('Eggs', 7)]
7                           [('Coffee', 2), ('Eggs', 3)]
8      [('Cereal', 7), ('Pancake', 8), ('Coffee', 4),...
9      [('Cereal', 3), ('Eggs', 1), ('Coffee', 1), ('...

I also tried to convert to lists:

orderTypeLst = df(['order_type'])['order_items'].apply(list)

and then extract the lists by doing this:

breakFast=orderTypeLst['Breakfast']
lunch=orderTypeLst['Lunch']
dinner=orderTypeLst['Dinner']

but the output is a string. And I can’t iterate through that either.

["[('Coffee', 4), ('Eggs', 7)]",
 "[('Coffee', 2), ('Eggs', 3)]",
 "[('Cereal', 7), ('Pancake', 8), ('Coffee', 4), ('Eggs', 8)]"]

As for dictionaries I tried the below, but the output is duplicated:

pd.Series(outlierFile.order_type.values,index=outlierFile.order_items).to_dict()

output sample

 "[('Fries', 1), ('Steak', 6), ('Salad', 8), ('Chicken', 10)]": 'Lunch',
 "[('Cereal', 6), ('Pancake', 8), ('Eggs', 3)]": 'Breakfast',
 "[('Shrimp', 9), ('Salmon', 9)]": 'Dinner',
 "[('Pancake', 3), ('Coffee', 5)]": 'Breakfast',
 "[('Eggs', 1), ('Pancake', 1), ('Coffee', 5), ('Cereal', 5)]": 'Breakfast'

my desired output is a clean version of each order_type (list or dictionary) so I can iterate through the tuples and extract the needed items.


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2024-12-26

共1个答案

小能豆

To achieve your goal of extracting the menu items and their quantities based on the order_type column (Breakfast, Lunch, Dinner), while cleaning up the data for easy iteration, you can proceed with the following steps:

1. Filter rows based on the order_type

You correctly filtered the rows using df.loc, but the data was returned as a Series where each entry was a list of tuples, and this is why it looked like a string.

2. Ensure proper iteration over the tuple data

To easily iterate through the menu items and quantities, you need to process the order_items column correctly. Since order_items is a list of tuples, you can extract the information by iterating over the filtered DataFrame.

Here’s how to clean up your process:

Solution

import pandas as pd

# Sample data
data = {
    'order_id': [45, 12, 44, 23],
    'order_type': ['Lunch', 'Dinner', 'Lunch', 'Breakfast'],
    'order_items': [
        [('Burger', 5), ('Fries', 6)],
        [('Shrimp', 10), ('Fish&Chips', 7)],
        [('Salad', 9), ('Steak', 9)],
        [('Coffee', 2), ('Eggs', 3)]
    ]
}

df = pd.DataFrame(data)

# Filter the rows based on order_type
breakfast_orders = df.loc[df['order_type'] == 'Breakfast', 'order_items']
lunch_orders = df.loc[df['order_type'] == 'Lunch', 'order_items']
dinner_orders = df.loc[df['order_type'] == 'Dinner', 'order_items']

# Extract the menu items and quantities as dictionaries
breakfast_menu = []
lunch_menu = []
dinner_menu = []

# Iterate through each order and extract the items and quantities
for order in breakfast_orders:
    for item, quantity in order:
        breakfast_menu.append((item, quantity))

for order in lunch_orders:
    for item, quantity in order:
        lunch_menu.append((item, quantity))

for order in dinner_orders:
    for item, quantity in order:
        dinner_menu.append((item, quantity))

# Print the results for each menu
print("Breakfast Menu:", breakfast_menu)
print("Lunch Menu:", lunch_menu)
print("Dinner Menu:", dinner_menu)

Explanation

  1. Filter by order_type: You use df.loc to filter out rows based on the order_type column (Breakfast, Lunch, or Dinner).

  2. Iterate through each list of tuples: The order_items column contains a list of tuples like [('Burger', 5), ('Fries', 6)]. You loop through each list (filtered by order_type) and extract the item names and quantities.

  3. Store the results in lists: After extracting the items and quantities, you store them in breakfast_menu, lunch_menu, or dinner_menu as a list of tuples, making it easier to work with them.

Output

This will give you the following output:

Breakfast Menu: [('Coffee', 2), ('Eggs', 3)]
Lunch Menu: [('Burger', 5), ('Fries', 6), ('Salad', 9), ('Steak', 9)]
Dinner Menu: [('Shrimp', 10), ('Fish&Chips', 7)]

3. (Optional) If you want a dictionary by order_type

If you want to store each menu type in a dictionary for easier access, you can modify the code as follows:

# Create a dictionary to hold the menus by order_type
menu_dict = {
    'Breakfast': [],
    'Lunch': [],
    'Dinner': []
}

# Populate the dictionary
for order_type in ['Breakfast', 'Lunch', 'Dinner']:
    orders = df.loc[df['order_type'] == order_type, 'order_items']
    for order in orders:
        for item, quantity in order:
            menu_dict[order_type].append((item, quantity))

# Print the dictionary
print(menu_dict)

Output:

{
    'Breakfast': [('Coffee', 2), ('Eggs', 3)],
    'Lunch': [('Burger', 5), ('Fries', 6), ('Salad', 9), ('Steak', 9)],
    'Dinner': [('Shrimp', 10), ('Fish&Chips', 7)]
}

This approach organizes the menu items into a dictionary where each order_type is a key, and the associated value is the list of items and quantities.

Conclusion

By filtering the DataFrame and iterating over the order_items column, you can extract the menu items and their quantities into a more usable format, whether that’s a list or a dictionary. You can easily iterate over this cleaned-up data and perform further analysis or processing as needed.

2024-12-26