The column names (which are strings) cannot be sliced in the manner you tried. Here you have a couple of options. If you know from context which variables you want to slice out, you can just return a view of only those columns by passing a list into the __getitem__ syntax (the []’s). Alternatively, if … Read more
No. Regular expressions in Python are handled by the re module. In general:
If you don’t want to worry about speed (and with 155 columns you probably don’t care) you can use the t.test function and apply it to every column. Simulate some data first Then we can apply the t.test function to all but the first column using the formula argument. which returns the test statistic for … Read more
Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course they do not exist yet). To create such a “default” item, it calls the … Read more
Yes, it was added in version 2.5. The expression syntax is: First condition is evaluated, then exactly one of either a or b is evaluated and returned based on the Boolean value of condition. If condition evaluates to True, then a is evaluated and returned but b is ignored, or else when b is evaluated … Read more
Here’s an answer to the same question you’re asking: https://stackoverflow.com/a/2866456/4380308 Or you can use the ‘timeit’ module: https://stackoverflow.com/a/2866460/4380308
A context free grammar is a grammar which satisfies certain properties. In computer science, grammars describe languages; specifically, they describe formal languages. A formal language is just a set (mathematical term for a collection of objects) of strings (sequences of symbols… very similar to the programming usage of the word “string”). A simple example of … Read more
From RFC 5321, section 2.3.11: The standard mailbox naming convention is defined to be “local-part@domain”; contemporary usage permits a much broader set of applications than simple “user names”. Consequently, and due to a long history of problems when intermediate hosts have attempted to optimize transport by modifying them, the local-part MUST be interpreted and assigned … Read more
The problem C++ includes useful generic functions like std::for_each and std::transform, which can be very handy. Unfortunately they can also be quite cumbersome to use, particularly if the functor you would like to apply is unique to the particular function. If you only use f once and in that specific place it seems overkill to … Read more
I want to compare values from two different files.In Notepad++ version 5.0.3 we had shortcut button Alt+d but in version 6.6.8 I cannot find any option to compare. Also let me know which version is most stable.