Data Engineers
Free Data Engineering Ebooks & Courses
Show more📈 Analytical overview of Telegram channel Data Engineers
Channel Data Engineers (@sql_engineer) in the English language segment is an active participant. Currently, the community unites 10 371 subscribers, ranking 19 370 in the Education category and 40 181 in the India region.
📊 Audience metrics and dynamics
Since its creation on невідомо, the project has demonstrated rapid growth, gathering an audience of 10 371 subscribers.
According to the latest data from 08 June, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 245 over the last 30 days and by 13 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 10.67%. Within the first 24 hours after publication, content typically collects 2.43% reactions from the total number of subscribers.
- Post reach: On average, each post receives 1 106 views. Within the first day, a publication typically gains 252 views.
- Reactions and interaction: The audience actively supports content: the average number of reactions per post is 5.
- Thematic interests: Content is focused on key topics such as sql, learning, analytic, engineer, link:-.
📝 Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
“Free Data Engineering Ebooks & Courses”
Thanks to the high frequency of updates (latest data received on 09 June, 2026), the channel maintains relevance and a high level of publication reach. Analytics show that the audience actively interacts with content, making it an important point of influence in the Education category.
# Load the DataFrame
df = spark.read.csv("path/to/data.csv", header=True, inferSchema=True)
# Handle missing values
df_filled = df.fillna(0)
# Aggregate data
from pyspark.sql.functions import sum, col
df_aggregated = df_filled.groupBy("category", "region").agg(sum(col("sales")).alias("total_sales"))
# Sort the results
df_aggregated_sorted = df_aggregated.orderBy("total_sales", ascending=False)
# Save the aggregated DataFrame
df_aggregated_sorted.write.csv("path/to/aggregated/data.csv", header=True)
Scenario 2: Data Transformation
Interviewer: "How would you transform a DataFrame by converting a column to timestamp, handling invalid dates and extracting specific date components?"
Candidate:
# Load the DataFrame
df = spark.read.csv("path/to/data.csv", header=True, inferSchema=True)
# Convert column to timestamp
from pyspark.sql.functions import to_timestamp, col
df_transformed = df.withColumn("date_column", to_timestamp(col("date_column"), "yyyy-MM-dd"))
# Handle invalid dates
df_transformed_filtered = df_transformed.filter(col("date_column").isNotNull())
# Extract date components
from pyspark.sql.functions import year, month, dayofmonth
df_transformed_extracted = df_transformed_filtered.withColumn("year", year(col("date_column"))).withColumn("month", month(col("date_column"))).withColumn("day", dayofmonth(col("date_column")))
# Save the transformed DataFrame
df_transformed_extracted.write.csv("path/to/transformed/data.csv", header=True)
Scenario 3: Data Partitioning
Interviewer: "How would you partition a large DataFrame by date and save it to parquet format, handling data skewness and optimizing storage?"
Candidate:
# Load the DataFrame
df = spark.read.csv("path/to/data.csv", header=True, inferSchema=True)
# Partition by date
df_partitioned = df.repartitionByRange("date_column")
# Save to parquet format
df_partitioned.write.parquet("path/to/partitioned/data.parquet", partitionBy=["date_column"])
# Optimize storage
df_partitioned.write.option("compression", "snappy").parquet("path/to/partitioned/data.parquet", partitionBy=["date_column"])
Here, you can find Data Engineering Resources 👇
https://topmate.io/analyst/910180
All the best 👍👍from pyspark.sql.functions import when, isnan
# Load the DataFrame
df = spark.read.csv("path/to/data.csv", header=True, inferSchema=True)
# Check for missing values
missing_count = df.select([count(when(isnan(c), c)).alias(c) for c in df.columns])
# Replace missing values with mean
from pyspark.sql.functions import mean
mean_values = df.agg(*[mean(c).alias(c) for c in df.columns])
df_filled = df.fillna(mean_values)
# Save the cleaned DataFrame
df_filled.write.csv("path/to/cleaned/data.csv", header=True)
Interviewer: "That's correct! Can you explain why you used the fillna() method?"
Candidate: "Yes, fillna() replaces missing values with the specified value, in this case, the mean of each column."
*Scenario 2: Data Aggregation*
Interviewer: "How would you aggregate data by category and calculate the average sales amount?"
Candidate:
# Load the DataFrame
df = spark.read.csv("path/to/data.csv", header=True, inferSchema=True)
# Aggregate data by category
from pyspark.sql.functions import avg
df_aggregated = df.groupBy("category").agg(avg("sales").alias("avg_sales"))
# Sort the results
df_aggregated_sorted = df_aggregated.orderBy("avg_sales", ascending=False)
# Save the aggregated DataFrame
df_aggregated_sorted.write.csv("path/to/aggregated/data.csv", header=True)
Interviewer: "Great answer! Can you explain why you used the groupBy() method?"
Candidate: "Yes, groupBy() groups the data by the specified column, in this case, 'category', allowing us to perform aggregation operations."
Here, you can find Data Engineering Resources 👇
https://topmate.io/analyst/910180
All the best 👍👍
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