07c12c09a7
## What changes were proposed in this pull request?
This PR proposes to support _not_ trimming the white spaces when writing out. These are `false` by default in CSV reading path but these are `true` by default in CSV writing in univocity parser.
Both `ignoreLeadingWhiteSpace` and `ignoreTrailingWhiteSpace` options are not being used for writing and therefore, we are always trimming the white spaces.
It seems we should provide a way to keep this white spaces easily.
WIth the data below:
```scala
val df = spark.read.csv(Seq("a , b , c").toDS)
df.show()
```
```
+---+----+---+
|_c0| _c1|_c2|
+---+----+---+
| a | b | c|
+---+----+---+
```
**Before**
```scala
df.write.csv("/tmp/text.csv")
spark.read.text("/tmp/text.csv").show()
```
```
+-----+
|value|
+-----+
|a,b,c|
+-----+
```
It seems this can't be worked around via `quoteAll` too.
```scala
df.write.option("quoteAll", true).csv("/tmp/text.csv")
spark.read.text("/tmp/text.csv").show()
```
```
+-----------+
| value|
+-----------+
|"a","b","c"|
+-----------+
```
**After**
```scala
df.write.option("ignoreLeadingWhiteSpace", false).option("ignoreTrailingWhiteSpace", false).csv("/tmp/text.csv")
spark.read.text("/tmp/text.csv").show()
```
```
+----------+
| value|
+----------+
|a , b , c|
+----------+
```
Note that this case is possible in R
```r
> system("cat text.csv")
f1,f2,f3
a , b , c
> df <- read.csv(file="text.csv")
> df
f1 f2 f3
1 a b c
> write.csv(df, file="text1.csv", quote=F, row.names=F)
> system("cat text1.csv")
f1,f2,f3
a , b , c
```
## How was this patch tested?
Unit tests in `CSVSuite` and manual tests for Python.
Author: hyukjinkwon <gurwls223@gmail.com>
Closes #17310 from HyukjinKwon/SPARK-18579.
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|---|---|---|
| .. | ||
| docs | ||
| lib | ||
| pyspark | ||
| test_support | ||
| .gitignore | ||
| MANIFEST.in | ||
| pylintrc | ||
| README.md | ||
| run-tests | ||
| run-tests.py | ||
| setup.cfg | ||
| setup.py | ||
Apache Spark
Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Spark Streaming for stream processing.
Online Documentation
You can find the latest Spark documentation, including a programming guide, on the project web page
Python Packaging
This README file only contains basic information related to pip installed PySpark. This packaging is currently experimental and may change in future versions (although we will do our best to keep compatibility). Using PySpark requires the Spark JARs, and if you are building this from source please see the builder instructions at "Building Spark".
The Python packaging for Spark is not intended to replace all of the other use cases. This Python packaged version of Spark is suitable for interacting with an existing cluster (be it Spark standalone, YARN, or Mesos) - but does not contain the tools required to setup your own standalone Spark cluster. You can download the full version of Spark from the Apache Spark downloads page.
NOTE: If you are using this with a Spark standalone cluster you must ensure that the version (including minor version) matches or you may experience odd errors.
Python Requirements
At its core PySpark depends on Py4J (currently version 0.10.4), but additional sub-packages have their own requirements (including numpy and pandas).