python 2d array and rows and cols

#make array

W = 2

H = 3

list2d = []

for i in range(0,H):

w_list =[]

for j in range (0,W):

w_list.append((i,j))

list2d.append(w_list)

#print 2d array

print(list2d)

#get row and col

Height = Rows = len(list2d)

Width = Cols = len(list2d[0])

#check values

print( Rows, Cols)

print( Height, Width)

#print all elements

for i in range(0,Rows):

for j in range (0,Cols):

print(list2d[i][j])

output

[[(0, 0), (0, 1)], [(1, 0), (1, 1)], [(2, 0), (2, 1)]]
3 2
3 2
(0, 0)
(0, 1)
(1, 0)
(1, 1)
(2, 0)
(2, 1)

python dic to json, json to txt file (example source code)

This article is about how to convert dic type to json.

source code is like that:
Dic -> Json -> txt file 1
txt file 1 -> Json -> Dic -> Json -> txt file 2

So consequentially, txt file1 and txt file 2 would be same.

Then check source code.

#dictionary type

dic_type = {'dic_type': 'yes', 'json': 10}

#dic to json

import json

str_type = json.dumps(dic_type) #dic to json

#write json to file

f= open("./json.txt","w+")

f.write(str_type)

f.close

#dic from json

dic_type_from_json = json.loads(str_type)

#dic from file

f = open("./json.txt","r")

str_type_from_file = f.read()

f.close

dic_type_from_file = json.loads(str_type_from_file)

#check data type

print( type(str_type) )#Output str

print( type(dic_type_from_json) )#Output dict

print( type(dic_type_from_file) )#Output dict

#write json to file

f= open("./json2.txt","w+")

r = json.dumps(dic_type_from_file)

f.write(r)

f.close

#json.txt and json2.txt is same

64base image to pil image and upload s3 bucket on aws lambda

This article is about how to convert base64 string image to byte and invoke to PIL image.
Then we can handle image whatever we want to ex) image resize ..

base64 image come from img_base64 = event['base64Image']
and then convert to byte data imgdata = base64.b64decode(img_base64)

then it can save to image file and load to Image.open(filename)
or
invoke to pil image directly : img2 = Image.open(io.BytesIO(imgdata))

In the source code, there is also example how to upload image to s3 bucket.
refer to below code.
//

import sys
sys.path.append("/opt")

import json
import boto3
import os
import io
from PIL import Image
import base64



ACCESS_KEY = os.environ.get('ACCESS_KEY')
SECRET_KEY = os.environ.get('SECRET_KEY')

def uploadToS3(bucket, s3_path, local_path):
    s3_client = boto3.client(
        's3',
        aws_access_key_id=ACCESS_KEY,
        aws_secret_access_key=SECRET_KEY,
    )
    s3_client.upload_file(local_path, bucket, s3_path)
    
    
    
def lambda_handler(event, context):
    
    #base64 image string
    img_base64 = event['base64Image']
    #string to byte
    imgdata = base64.b64decode(img_base64)
    
    #save some image file
    with open("/tmp/imageToSave.png", "wb") as fh:
        fh.write(imgdata)
    
    #open("/tmp/imageToSave.png",'rb')
    uploadToS3("input-image1", "imageToSave.png", "/tmp/imageToSave.png")
    
    #load image file to pil
    img = Image.open("/tmp/imageToSave.png")
    width, height = img.size
    
    #load 
    img2 = Image.open(io.BytesIO(imgdata))
    width2, height2 = img2.size
    
    # TODO implement
    return {
        'statusCode': 200,
        'body': json.dumps('Hello leon it is from Lambda!'),
        'width file': width,
        'heihgt file' : height,
        'width pil': width2,
        'heihgt pil' : height2
    }

//

These method is referenced by:
https://stackoverflow.com/questions/16214190/how-to-convert-base64-string-to-image
https://stackoverflow.com/questions/11727598/pil-image-open-working-for-some-images-but-not-others
https://stackoverflow.com/questions/16214190/how-to-convert-base64-string-to-image
https://stackoverflow.com/questions/6444548/how-do-i-get-the-picture-size-with-pil

Thanks for effort.