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import pyarrow.parquet as pq
import os
import json
# Function to check row count in a Parquet file
def check_row_count(parquet_file_path):
try:
parquet_file = pq.ParquetFile(parquet_file_path)
num_rows = parquet_file.metadata.num_rows
print(f"The Parquet file '{parquet_file_path}' contains {num_rows} rows.")
return num_rows
except Exception as e:
print(f"Error reading Parquet file: {e}")
# Function to retrieve a specific row efficiently from a Parquet file
def get_specific_row(parquet_file_path, row_index):
try:
# Open the Parquet file
parquet_file = pq.ParquetFile(parquet_file_path)
# Initialize variables to track the current row position
current_row = 0
# Iterate over each row group in the Parquet file
for row_group in range(parquet_file.num_row_groups):
# Read the current row group into a table
table = parquet_file.read_row_group(row_group)
# Check if the desired row is within the current row group
if current_row <= row_index < current_row + table.num_rows:
# Calculate the index of the row within the current table
row_in_table = row_index - current_row
# Retrieve the row as a dictionary
row = {col: table.column(col)[row_in_table].as_py() for col in table.column_names}
return row
# Update the current row position
current_row += table.num_rows
# If the row index is out of bounds, raise an error
raise IndexError(f"Row index {row_index} is out of bounds.")
except Exception as e:
print(f"Error retrieving row: {e}")
return None
# Function to save image content back to JPG
def save_image_from_row(row, output_image_path):
try:
image_content = row['image_content'] # Image content as binary
with open(output_image_path, 'wb') as img_file:
img_file.write(image_content)
print(f"Image saved successfully at {output_image_path}")
except Exception as e:
print(f"Error saving image: {e}")
# Function to save JSON content to a file
def save_json_from_row(row, output_json_path):
try:
json_content = row['json_content'] # JSON content as string
json_data = json.loads(json_content) # Parse the string into a JSON object
with open(output_json_path, 'w', encoding='utf-8') as json_file:
json.dump(json_data, json_file, indent=4, ensure_ascii=False)
print(f"JSON saved successfully at {output_json_path}")
except Exception as e:
print(f"Error saving JSON: {e}")
# Function to save all images and JSONs into a specific folder
def save_all_images_and_jsons(parquet_file_path, output_folder):
try:
# Create the output folder if it doesn't exist
os.makedirs(output_folder, exist_ok=True)
# Open the Parquet file and check the number of rows
parquet_file = pq.ParquetFile(parquet_file_path)
num_rows = parquet_file.metadata.num_rows
# Iterate through all rows and save images and JSONs
for row_index in range(num_rows):
row = get_specific_row(parquet_file_path, row_index)
if row is not None:
# Define the file paths for each image and JSON
output_image_path = os.path.join(output_folder, f"image_{row_index}.jpg")
output_json_path = os.path.join(output_folder, f"data_{row_index}.json")
# Save the image and JSON content
save_image_from_row(row, output_image_path)
save_json_from_row(row, output_json_path)
except Exception as e:
print(f"Error saving all images and JSONs: {e}")
# Function to save N images and JSONs into a specific folder
def save_n_images_and_jsons(parquet_file_path, output_folder, num_to_save):
try:
# Create the output folder if it doesn't exist
os.makedirs(output_folder, exist_ok=True)
# Open the Parquet file and check the number of rows
parquet_file = pq.ParquetFile(parquet_file_path)
num_rows = parquet_file.metadata.num_rows
# Limit the number of files to save to the available rows
limit = min(num_to_save, num_rows)
# Iterate through the first N rows and save images and JSONs
for row_index in range(limit):
row = get_specific_row(parquet_file_path, row_index)
if row is not None:
# Define the file paths for each image and JSON
output_image_path = os.path.join(output_folder, f"image_{row_index}.jpg")
output_json_path = os.path.join(output_folder, f"data_{row_index}.json")
# Save the image and JSON content
save_image_from_row(row, output_image_path)
save_json_from_row(row, output_json_path)
except Exception as e:
print(f"Error saving N images and JSONs: {e}")
# Example usage:
parquet_file_path = 'path/to/MobileViews_xxx-xxx.parquet'
output_folder_all = 'path/to/all_extracted_images_jsons'
output_folder_n = 'path/to/n_extracted_images_jsons'
check_row_count('parquet_file_path')
# Step 1: Save all images and JSONs or a certain number
save_n_images_and_jsons(parquet_file_path, output_folder_n, num_to_save=100)
# save_all_images_and_jsons(parquet_file_path, output_folder_all)
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