removed lambda from sortByKey()

[udoklein]

According to the documentation the sortByKey method does not take a lambda as an argument, thus the example is flawed. Removed the argument completely as this will default to ascending sort.

[srowen]

@udoklein can you survey all examples and put any changes you find into one PR?
It looks like sortByKey does take a lambda keyfunc?

    def sortByKey(self, ascending=True, numPartitions=None, keyfunc=lambda x: x):

[udoklein]

Good point. The documentation did not mention the keyfunc. However it is somewhat pointless to add the default as an argument. In particular if the default is lambda x: x. Conclusion: the documentation should be fixed instead. (http://spark.apache.org/docs/latest/programming-guide.html) Where would I find the sources for the programming guide?

[srowen]

Look for docs/programming-guide.md

[srowen]

@udoklein if you want to update the docs that's fine too -- let me know if you intend to, or want o merge as is

[udoklein]

Well, in order to fix the documentation I would need to understand how to properly document it such that it is also valid for other languages (Java / Scala). Since I am a beginner I do not. I double checked that the example was definitely bogus. If the function is replaced by lambda x: -x it does not change the sort order. I suggest to just merge as is.

[srowen]

It's not an issue in other languages since the other APIs don't take a function in sortByKey. I'm actually not sure why it exists here. The example isn't bogus right, just redundant? reversing the sign of the keys would definitely change the order right? or are you saying the method doesn't work?

[udoklein]

As I said, changing the sign does NOT change the sort order. The example is bogus. The lambda would have to be either the third argument or it has to be passed as a named argument. The way it is passed passes it into the first argument.

[srowen]

Ah, that's the point. Yes, needs a fix for sure.

[SparkQA]

Test build #2359 has finished for PR 10640 at commit 1282559.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

Merged to master/1.6/1.5