Tutorial by Examples: w

WTForms provides a FileField to render a file type input. It doesn't do anything special with the uploaded data. However, since Flask splits the form data (request.form) and the file data (request.files), you need to make sure to pass the correct data when creating the form. You can use a Combine...

An enumerations value in no way needs to be unique: #include <stdlib.h> /* for EXIT_SUCCESS */ #include <stdio.h> /* for printf() */ enum Dupes { Base, /* Takes 0 */ One, /* Takes Base + 1 */ Two, /* Takes One + 1 */ Negative = -1, AnotherZero /* Takes Negativ...

CROSS APPLY enables you to "join" rows from a table with dynamically generated rows returned by some table-value function. Imagine that you have a Company table with a column that contains an array of products (ProductList column), and a function that parse these values and returns a set ...

CROSS APPLY enables you to "join" rows from a table with collection of JSON objects stored in a column. Imagine that you have a Company table with a column that contains an array of products (ProductList column) formatted as JSON array. OPENJSON table value function can parse these values...

If you store a list of tags in a row as coma separated values, STRING_SPLIT function enables you to transform list of tags into a table of values. CROSS APPLY enables you to "join" values parsed by STRING_SPLIT function with a parent row. Imagine that you have a Product table with a colu...

In Julia, when looping through an iterable object I is done with the for syntax: for i = I # or "for i in I" # body end Behind the scenes, this is translated to: state = start(I) while !done(I, state) (i, state) = next(I, state) # body end Therefore, if you wan...

When the shell performs parameter expansion, command substitution, variable or arithmetic expansion, it scans for word boundaries in the result. If any word boundary is found, then the result is split into multiple words at that position. The word boundary is defined by a shell variable IFS (Interna...

See what, when and why if you don't know about the affiliation of IFS to word splitting let's set the IFS to space character only: set -x var='I am a multiline string' IFS=' ' fun() { echo "-$1-" echo "*$2*" echo ".$3." } fun $var This time wo...

$ a='I am a string with spaces' $ [ $a = $a ] || echo "didn't match" bash: [: too many arguments didn't match [ $a = $a ] was interpreted as [ I am a string with spaces = I am a string with spaces ]. [ is the test command for which I am a string with spaces is not a single argument...

There are some cases where word splitting can be useful: Filling up array: arr=($(grep -o '[0-9]\+' file)) This will fill up arr with all numeric values found in file Looping through space separated words: words='foo bar baz' for w in $words;do echo "W: $w" done Output...

The following function reads an entire file into a new string and returns it: (defun read-file (infile) (with-open-file (instream infile :direction :input :if-does-not-exist nil) (when instream (let ((string (make-string (file-length instream)))) (read-sequence string instr...

SET TEST=0 IF %TEST% == 0 ( echo TEST FAILED ) ELSE IF %TEST% == 1 ( echo TEST PASSED ) ELSE ( echo TEST INVALID )

To download NetBeans IDE just visit the NetBeans site and download the proper version of the IDE based on your OS, Architecture and technologies. You can select from the following technologies: Java SE. Supports all standard Java SE development features as well as support for NetBeans Platform ...

Enumeration types can also be declared without giving them a name: enum { buffersize = 256, }; static unsigned char buffer [buffersize] = { 0 }; This enables us to define compile time constants of type int that can as in this example be used as array length.

Setup An Electron project structure usually looks like this: hello-world-app/ ├── package.json ├── index.js └── index.html Now let's create the files and initialize our package.json. $ mkdir hello-world-app && cd hello-world-app $ touch index.js $ touch index.html $ npm init N...

These two properties work in a similar fashion as the overflow property and accept the same values. The overflow-x parameter works only on the x or left-to-right axis. The overflow-y works on the y or top-to-bottom axis. HTML <div id="div-x"> If this div is too small to displa...

Wrapper script is a script that wraps another script or command to provide extra functionalities or just to make something less tedious. For example, the actual egrep in new GNU/Linux system is being replaced by a wrapper script named egrep. This is how it looks: #!/bin/sh exec grep -E "$@&q...

You can have functions in the PS1 variable, just make sure to single quote it or use escape for special chars: gitPS1(){ gitps1=$(git branch 2>/dev/null | grep '*') gitps1="${gitps1:+ (${gitps1/#\* /})}" echo "$gitps1" } PS1='\u@\h:\w$(gitPS1)$ ' It will...

timeNow(){ echo "$(date +%r)" } PS1='[$(timeNow)] \u@\h:\w$ ' It will give you a prompt like this: [05:34:37 PM] user@Host:/path$ Notes: Make the changes in ~/.bashrc or /etc/bashrc or ~/.bash_profile or ~./profile file (depending on the OS) and save it. Run source ~/.ba...

Create a simple DataFrame. import numpy as np import pandas as pd # Set the seed so that the numbers can be reproduced. np.random.seed(0) df = pd.DataFrame(np.random.randn(5, 3), columns=list('ABC')) # Another way to set column names is "columns=['column_1_name','column_2_name','c...