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Removing first x characters from string?
How might one remove the first x characters from a string? For example, if one had a string lipsum , how would they remove the first 3 characters and get a result of sum ?
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Get the first element of each tuple in a list in Python [duplicate]
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Use a list comprehension:
res_list = [x[0] for x in rows]
Below is a demonstration:
>>> rows = [(1, 2), (3, 4), (5, 6)]
>>> [x[0] for x in rows]
[1, 3, 5]
>>>
Alternately, you could use unpacking instead of x[0]:
res_list = [x f...
Is it Pythonic to use list comprehensions for just side effects?
...t is created, and it could potentially be very, very large, and therefore expensive to create.
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Why does Go have a “goto” statement
... standard library, we can see where gotos are actually well applied.
For example, in the math/gamma.go file, the goto statement is used:
for x < 0 {
if x > -1e-09 {
goto small
}
z = z / x
x = x + 1
}
for x < 2 {
if x < 1e-09 {
goto small
}
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How can a Java variable be different from itself?
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One simple way is to use Float.NaN:
float x = Float.NaN; // <--
if (x == x) {
System.out.println("Ok");
} else {
System.out.println("Not ok");
}
Not ok
You can do the same with Double.NaN.
From JLS §15.21.1. Numerical Equality Operators == and !=:
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Batch script loop
I need to execute a command 100-200 times, and so far my research indicates that I would either have to copy/paste 100 copies of this command, OR use a for loop, but the for loop expects a list of items, hence I would need 200 files to operate on, or a list of 200 items, defeating the point.
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Increase number of axis ticks
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You can override ggplots default scales by modifying scale_x_continuous and/or scale_y_continuous. For example:
library(ggplot2)
dat <- data.frame(x = rnorm(100), y = rnorm(100))
ggplot(dat, aes(x,y)) +
geom_point()
Gives you this:
And overriding the scales can give you s...
Which is better option to use for dividing an integer number by 2?
... treating it as a numerical value, use division.
Note that they are not exactly equivalent. They can give different results for negative integers. For example:
-5 / 2 = -2
-5 >> 1 = -3
(ideone)
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Set value for particular cell in pandas DataFrame using index
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RukTech's answer, df.set_value('C', 'x', 10), is far and away faster than the options I've suggested below. However, it has been slated for deprecation.
Going forward, the recommended method is .iat/.at.
Why df.xs('C')['x']=10 does not work:
df.xs('C') by d...
What's the difference between lists enclosed by square brackets and parentheses in Python?
...es.
A list is mutable, meaning you can change its contents:
>>> x = [1,2]
>>> x.append(3)
>>> x
[1, 2, 3]
while tuples are not:
>>> x = (1,2)
>>> x
(1, 2)
>>> x.append(3)
Traceback (most recent call last):
File "<stdin>", line 1, in ...