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Identify if a string is a number
...
int n;
bool isNumeric = int.TryParse("123", out n);
Update As of C# 7:
var isNumeric = int.TryParse("123", out int n);
or if you don't need the number you can discard the out parameter
var isNumeric = int.TryParse("123", out _);
The var s can be replaced ...
How to represent multiple conditions in a shell if statement?
...
Classic technique (escape metacharacters):
if [ \( "$g" -eq 1 -a "$c" = "123" \) -o \( "$g" -eq 2 -a "$c" = "456" \) ]
then echo abc
else echo efg
fi
I've enclosed the references to $g in double quotes; that's good practice, in general. Strictly, the parentheses aren't needed because the preced...
Hg: How to do a rebase like git's rebase
...e:
1. Start working on a new feature:
$ hg clone mainline-repo newfeature-123
do a few commits (M, N, O)
master A---B---C
\
newfeature-123 M---N---O
2. Pull new changes from upstream mainline:
$ hg pull
master A---B---C---D---E---F
\
newfeature-123 M---N---O
...
Linq code to select one item
...e extension methods directly like:
var item = Items.First(i => i.Id == 123);
And if you don't want to throw an error if the list is empty, use FirstOrDefault which returns the default value for the element type (null for reference types):
var item = Items.FirstOrDefault(i => i.Id == 123);
...
Why does PHP consider 0 to be equal to a string?
...alse.
But what if I do need to compare numbers as strings with numbers?
"123" === 123
evaluates false because the left and right term are of different type.
What is actually needed is a weak comparison without the pitfalls of PHP type juggling.
The solution is to explicit promote the terms to ...
Reshaping data.frame from wide to long format
... 1952 10,058
7: AFG Afghanistan 1953 23,557
8: ALB Albania 1953 11,123
9: AFG Afghanistan 1954 24,555
10: ALB Albania 1954 12,246
Some alternative notations:
melt(setDT(wide), id.vars = 1:2, variable.name = "year")
melt(setDT(wide), measure.vars = 3:7, variable.name = "year")
melt...
Blocks and yields in Ruby
... gift from foo!") if block_given?
end
foo(10)
# OK: called as foo(10)
foo(123) {|y| puts "BLOCK: #{y} How nice =)"}
# OK: called as foo(123)
# BLOCK: A gift from foo! How nice =)
Or, using the special block argument syntax:
def bar(x, &block)
puts "OK: called as bar(#{x.inspect})"
block....
How to convert a string to number in TypeScript?
...rrect typing and will correctly parse simple decimal integer strings like "123", but will behave differently for various other, possibly expected, cases (like "123.45") and corner cases (like null).
Table taken from this answer
...
Can functions be passed as parameters?
...ing.
func value(x int) string {
return fmt.Sprintf("%v", x)
}
// quote123 passes 123 to convert func and returns quoted string.
func quote123(fn convert) string {
return fmt.Sprintf("%q", fn(123))
}
func main() {
var result string
result = value(123)
fmt.Println(result)
//...
How can I remove all text after a character in bash?
...
@kp123: It's the first example in my answer. The second time I show it (where "tomorrow" is removed), it's almost exactly the situation you're asking about.
– Paused until further notice.
A...