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spark:spark-introduction [2022/12/14 12:36] straka [Word Count Example] |
spark:spark-introduction [2022/12/14 13:28] (current) straka [Running Spark Shell in Python] |
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===== Running Spark Shell in Python ===== | ===== Running Spark Shell in Python ===== | ||
- | To run interactive Python shell in local Spark mode, run (on your local workstation or on cluster using '' | + | To run interactive Python shell in local Spark mode, run (on your local workstation or on cluster using '' |
- | PYSPARK_DRIVER_PYTHON=ipython3 pyspark | + | |
The PYSPARK_DRIVER_PYTHON=ipython3 parameter instructs Spark to use '' | The PYSPARK_DRIVER_PYTHON=ipython3 parameter instructs Spark to use '' | ||
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We start by simple word count example. We load the RDD from text file, every line of the input file becoming an element of RDD. We then split every line into words, count every word occurrence and sort the words by the occurrences. Copy the following to the opened Python shell: | We start by simple word count example. We load the RDD from text file, every line of the input file becoming an element of RDD. We then split every line into words, count every word occurrence and sort the words by the occurrences. Copy the following to the opened Python shell: | ||
<file python> | <file python> | ||
- | wiki = sc.textFile("/ | + | wiki = sc.textFile("/ |
words = wiki.flatMap(lambda line: line.split()) | words = wiki.flatMap(lambda line: line.split()) | ||
counts = words.map(lambda word: (word, 1)).reduceByKey(lambda c1, c2: c1+c2) | counts = words.map(lambda word: (word, 1)).reduceByKey(lambda c1, c2: c1+c2) | ||
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# Alternatively, | # Alternatively, | ||
- | (sc.textFile("/ | + | (sc.textFile("/ |
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The Scala versions is quite similar: | The Scala versions is quite similar: | ||
<file scala> | <file scala> | ||
- | val wiki = sc.textFile("/ | + | val wiki = sc.textFile("/ |
val words = wiki.flatMap(line => line.split(" | val words = wiki.flatMap(line => line.split(" | ||
val counts = words.map(word => (word, 1)).reduceByKey((c1, | val counts = words.map(word => (word, 1)).reduceByKey((c1, | ||
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// Alternatively without variables and using placeholders in lambda parameters: | // Alternatively without variables and using placeholders in lambda parameters: | ||
- | (sc.textFile("/ | + | (sc.textFile("/ |
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===== K-Means Example ===== | ===== K-Means Example ===== | ||
- | An example implementing [[http:// | + | An example implementing [[http:// |
<file python> | <file python> | ||
import numpy as np | import numpy as np | ||
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data = lines.map(lambda line: np.array(map(float, | data = lines.map(lambda line: np.array(map(float, | ||
- | K = 50 | + | K = 100 |
epsilon = 1e-3 | epsilon = 1e-3 | ||
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val data = lines.map(line => Vector(line.split(" | val data = lines.map(line => Vector(line.split(" | ||
- | val K = 50 | + | val K = 100 |
val epsilon = 1e-3 | val epsilon = 1e-3 | ||