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How to merge a list of lists with same type of items to a single list of items?
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Use the SelectMany extension method
list = listOfList.SelectMany(x => x).ToList();
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Merging two arrays in .NET
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In C# 3.0 you can use LINQ's Concat method to accomplish this easily:
int[] front = { 1, 2, 3, 4 };
int[] back = { 5, 6, 7, 8 };
int[] combined = front.Concat(back).ToArray();
In C# 2.0 you don't have such a direct way, but Array.Copy is probably the ...
What is the purpose of “!” and “?” at the end of method names?
... Beware, this isn't always the case. For example, Ruby Array#concat docs.ruby-lang.org/en/2.0.0/Array.html#method-i-concat. Where you can get burnt badly is something like MyActiveRecordModel.column_names.concat(...). Instead you must clone it before doing the concat.
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String concatenation in Ruby
I am looking for a more elegant way of concatenating strings in Ruby.
16 Answers
16
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PostgreSQL: Difference between text and varchar (character varying)
... article does detailed testing to show that the performance of inserts and selects for all 4 data types are similar. It also takes a detailed look at alternate ways on constraining the length when needed. Function based constraints or domains provide the advantage of instant increase of the length c...
Fastest way to flatten / un-flatten nested JSON objects
... Object.keys(obj).forEach(key => {
this.flatten(obj[key], prefix.concat(key), current)
})
} else {
current[prefix.join('.')] = obj
}
return current
}
Features and/or caveats
It only accepts JSON objects. So if you pass something like {a: () => {}} you might not get wh...
How to add an object to an array
...of two arrays
var x = ['a', 'b', 'c'];
var y = ['d', 'e', 'f'];
var z = x.concat(y);
// x = ['a', 'b', 'c'] (remains unchanged)
// y = ['d', 'e', 'f'] (remains unchanged)
// z = ['a', 'b', 'c', 'd', 'e', 'f']
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Prevent errors from breaking / crashing gulp watch
...coffee({
bare: true
}))
.on('error', swallowError)
.pipe(concat('application.js'))
.pipe(gulp.dest('dist/scripts'))
.pipe(rename({ suffix: '.min' }))
.pipe(uglify())
.pipe(gulp.dest('dist/scripts'))
.pipe(notify({ message: 'Scripts task complete' }));
});
With...
Different font size of strings in the same TextView
...spans together with a separator and all
CharSequence finalText = TextUtils.concat(span1, " ", span2);
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Best way to check for “empty or null value”
... '
Demo
Empty string equals any string of spaces when cast to char(n):
SELECT ''::char(5) = ''::char(5) AS eq1
, ''::char(5) = ' '::char(5) AS eq2
, ''::char(5) = ' '::char(5) AS eq3;
Result:
eq1 | eq2 | eq3
----+-----+----
t | t | t
Test for "null or empty string" w...