Creating DataFrames

Data Manipulation with pandas

Maggie Matsui

Senior Content Developer at DataCamp

Dictionaries

my_dict = {
    "key1": value1,
    "key2": value2,
    "key3": value3
}

my_dict["key1"]

value1

my_dict = {
    "title": "Charlotte's Web",
    "author": "E.B. White",
    "published": 1952
}

my_dict["title"]

Charlotte's Web

Creating DataFrames

From a list of dictionaries

Constructed row by row

Several dictionaries are shown inside square brackets, representing a list of dictionaries.

From a dictionary of lists

Constructed column by column

Several pairs of square brackets are shown inside a dictionary, representing a dictionary of lists.

List of dictionaries - by row

name	breed	height (cm)	weight (kg)	date of birth
Ginger	Dachshund	22	10	2019-03-14
Scout	Dalmatian	59	25	2019-05-09

list_of_dicts = [

    {"name": "Ginger", "breed": "Dachshund", "height_cm": 22,
    "weight_kg": 10, "date_of_birth": "2019-03-14"},

    {"name": "Scout", "breed": "Dalmatian", "height_cm": 59, 
    "weight_kg": 25, "date_of_birth": "2019-05-09"}

]

List of dictionaries - by row

name	breed	height (cm)	weight (kg)	date of birth
Ginger	Dachshund	22	10	2019-03-14
Scout	Dalmatian	59	25	2019-05-09

new_dogs = pd.DataFrame(list_of_dicts)
print(new_dogs)

     name      breed  height_cm  weight_kg date_of_birth
0  Ginger  Dachshund         22         10    2019-03-14
1   Scout  Dalmatian         59         25    2019-05-09

Dictionary of lists - by column

name	breed	height	weight	date of birth
Ginger	Dachshund	22	10	2019-03-14
Scout	Dalmatian	59	25	2019-05-09

Key = column name
Value = list of column values

dict_of_lists = {

    "name": ["Ginger", "Scout"],

    "breed": ["Dachshund", "Dalmatian"],

    "height_cm": [22, 59],

    "weight_kg": [10, 25],

    "date_of_birth": ["2019-03-14", 
    "2019-05-09"]

}

new_dogs = pd.DataFrame(dict_of_lists)

Dictionary of lists - by column

name	breed	height (cm)	weight (kg)	date of birth
Ginger	Dachshund	22	10	2019-03-14
Scout	Dalmatian	59	25	2019-05-09

print(new_dogs)

     name      breed  height_cm  weight_kg date_of_birth
0  Ginger  Dachshund         22         10    2019-03-14
1   Scout  Dalmatian         59         25    2019-05-09

Let's practice!

Data Manipulation with pandas