[PYTHON] How to use dictionary {}

What is a dictionary type?

{"a":1,"b":2,"c":3} This time  a,b,c→key  1,2,3→value Say.

Extract dictionary type elements

ta=df["a"]
>>>print(ta)

Execution result


>>>1

Use key to retrieve element (value) like this

Change dictionary type key

df["a"]=4
>>>print(df)

Reference result


>>>{"a":4,"b":2,"c":3}

Same as how to retrieve elements

Add key and value to dictionary type

df.setdefault("d",4)
>>>print(df)

Execution result


>>>{"a":1,"b":2,"c":3,"d":4}

You can add it by using setdefault (key, value) like this.

How to delete dictionary key and value

df.pop("d")
>>>print(df)

Execution result


>>>{"a":1,"b":2,"c":3}

You can delete it by using pop (key) like this

Recommended Posts

How to use dictionary {}
How to use xml.etree.ElementTree
How to use Python-shell
How to use tf.data
How to use virtualenv
How to use Seaboan
How to use image-match
How to use shogun
How to use Virtualenv
How to use numpy.vectorize
How to use pytest_report_header
How to use partial
How to use Bio.Phylo
How to use SymPy
How to use x-means
How to use WikiExtractor.py
How to use virtualenv
How to use Matplotlib
How to use iptables
How to use numpy
How to use TokyoTechFes2015
How to use venv
How to use Pyenv
How to use list []
How to use python-kabusapi
How to use OptParse
How to use return
How to use dotenv
How to use pyenv-virtualenv
How to use Go.mod
How to use imutils
How to use import
How to use Qt Designer
How to use search sorted
python3: How to use bottle (2)
Understand how to use django-filter
How to use the generator
How to use FastAPI ③ OpenAPI
How to use Python argparse
How to use IPython Notebook
How to use Pandas Rolling
[Note] How to use virtualenv
How to use redis-py Dictionaries
[Python] How to use checkio
[Go] How to use "... (3 periods)"
How to use Django's GeoIp2
[Python] How to use input ()
How to use the decorator
[Introduction] How to use open3d
How to use Python lambda
How to use Jupyter Notebook
[Python] How to use virtualenv
python3: How to use bottle (3)
python3: How to use bottle
How to use Google Colaboratory
How to use Python bytes
[Introduction to Udemy Python3 + Application] 27. How to use the dictionary
How to use the zip function
How to use the optparse module
How to use SWIG from waf
Summary of how to use pandas.DataFrame.loc