How to open CSV file in R when R says “no such file or directory”?
To throw out another option, why not set the working directory (preferably via a script) to the desktop using setwd(‘C:\John\Desktop’) and then read the files just using file names
What does “Could not find or load main class” mean?
The java <class-name> command syntax First of all, you need to understand the correct way to launch a program using the java (or javaw) command. The normal syntax1 is this: where <option> is a command line option (starting with a “-” character), <class-name> is a fully qualified Java class name, and <arg> is an arbitrary … Read more
Java String Split by “|”
ou must use: This is because the split method takes a regular expression, and | is one of the special characters. It means ‘or’. That means you are splitting by ” or ”, which is just ”. Therefore it will split between every character. You need two slashes because the first one is for escaping the actual \ in the string, since \ is Java’s escape … Read more
How to round to at most 2 decimal places, if necessary?
Use Math.round() : Or to be more specific and to ensure things like 1.005 round correctly, use Number.EPSILON :
How to get rid of the “No bootable medium found!” error in Virtual Box? [closed]
Follow the steps below: 1) Select your VM Instance. Go to Settings->Storage 2) Under the storage tree select the default image or “Empty”(which ever is present) 3) Under the attributes frame, click on the CD image and select “Choose a virtual CD/DVD disk file“ 4) Browse and select the image file(iso or what ever format) from the … Read more
Extract a substring using PowerShell
The -match operator tests a regex, combine it with the magic variable $matches to get your result Whenever in doubt about regex-y things, check out this site: http://www.regular-expressions.info
What does the list() function do in Python?
list() converts the iterable passed to it to a list. If the itertable is already a list then a shallow copy is returned, i.e only the outermost container is new rest of the objects are still the same.
Best way to return multiple values from a function? [closed]
Named tuples were added in 2.6 for this purpose. Also see os.stat for a similar builtin example. In recent versions of Python 3 (3.6+, I think), the new typing library got the NamedTuple class to make named tuples easier to create and more powerful. Inheriting from typing.NamedTuple lets you use docstrings, default values, and type annotations. Example (From the docs):
Does Python have a string ‘contains’ substring method?
You can use the in operator:
How to avoid Request Entity Too Large 413 error
How to fix it in NGINX? client_max_body_size To fix this, you need to increase the value of the client_max_body_size directive. This directive defines the maximum amount of data Nginx will accept in an HTTP request. By default this value is set to 1 megabyte, meaning if you attempt to upload a file larger than 1 … Read more