The best way to do this in Pandas is to use drop: df = df.drop(‘column_name’, axis=1) where 1 is the axis number (0 for rows and 1 for columns.) To delete the column without having to reassign df you can do: df.drop(‘column_name’, axis=1, inplace=True) Finally, to drop by column number instead of by column label, … Read more
The del statement removes an element: del d[key] Note that this mutates the existing dictionary, so the contents of the dictionary changes for anybody else who has a reference to the same instance. To return a new dictionary, make a copy of the dictionary: def removekey(d, key): r = dict(d) del r[key] return r The … Read more
It’s because any iterable can be joined (e.g, list, tuple, dict, set), but its contents and the “joiner” must be strings. For example: ‘_’.join([‘welcome’, ‘to’, ‘stack’, ‘overflow’]) ‘_’.join((‘welcome’, ‘to’, ‘stack’, ‘overflow’)) ‘welcome_to_stack_overflow’ Using something other than strings will raise the following error: TypeError: sequence item 0: expected str instance, int found
If you only want a single item’s count, use the count method: >>> [1, 2, 3, 4, 1, 4, 1].count(1) 3 Important: this is very slow if you are counting multiple different items Each count call goes over the entire list of n elements. Calling count in a loop n times means n * n … Read more
This code will read the entire file into memory and remove all whitespace characters (newlines and spaces) from the end of each line: with open(filename) as file: lines = file.readlines() lines = [line.rstrip() for line in lines] If you’re working with a large file, then you should instead read and process it line-by-line: with open(filename) … Read more
Use the type() builtin function: >>> i = 123 >>> type(i) <type ‘int’> >>> type(i) is int True >>> i = 123.456 >>> type(i) <type ‘float’> >>> type(i) is float True To check if a variable is of a given type, use isinstance: >>> i = 123 >>> isinstance(i, int) True >>> isinstance(i, (float, str, … Read more
There are two built-in functions that help you identify the type of an object. You can use type() if you need the exact type of an object, and isinstance() to check an object’s type against something. Usually, you want to use isinstance() most of the times since it is very robust and also supports type … Read more
Use del and specify the index of the element you want to delete: >>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> del a[-1] >>> a [0, 1, 2, 3, 4, 5, 6, 7, 8] Also supports slices: >>> del a[2:4] >>> a [0, 1, 4, 5, 6, 7, 8, … Read more
One way is to use Kivy: Open source Python library for rapid development of applications that make use of innovative user interfaces, such as multi-touch apps. Kivy runs on Linux, Windows, OS X, Android and iOS. You can run the same [python] code on all supported platforms. Kivy Showcase app
tl;dr: Because of different default settings in C++ requiring more system calls. By default, cin is synchronized with stdio, which causes it to avoid any input buffering. If you add this to the top of your main, you should see much better performance: std::ios_base::sync_with_stdio(false); Normally, when an input stream is buffered, instead of reading one … Read more