foo.split(',').length != number of ',' found in 'foo'?

Question

Maybe it's because it's end of day on a Friday, and I have already found a work-around, but this is killing me.

I am using Java but am .NET developer.

I have a string and I need to split it on semicolon comma. Let's say its a row in a CSV file who has 200 210 columns. line.split(',').length will be sometimes, 199, where count of ',' will be 208 OR 209. I find count in 2 different ways even to be sure (using a regex, then manually looping through and checking the character after losing my sanity).

What's the super-obvious-hit-face-on-desk thing I'm missing here? Why isn't foo.split(delim).length == CountOfOccurences(foo,delim) all the time, only sometimes?

thanks much

Answer 1

First, there's an obvious difference of one. If there are 200 columns, all with text, there are 199 commas. Second, Java drops trailing empty strings by default. You can change this by passing a negative number as the second argument.

"foo,,bar,baz,,".split(",")

is:

{foo,,bar,baz}

an array of 4 elements. But

"foo,,bar,baz,,".split(",", -1)

is::

{foo,,bar,baz,,}

with all 6.

Note that only trailing empty strings are dropped by default.

Finally, don't forget that the String is compiled into a regex. This is not be applicable here, since , is not a special character, but you should keep it in mind.