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Remove all occurrences of a value from a list?
... The code for habnabit's suggestion looks like this: [y for y in x if y != 2]
– coredumperror
Apr 22 '13 at 22:12
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How to find list intersection?
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If order is not important and you don't need to worry about duplicates then you can use set intersection:
>>> a = [1,2,3,4,5]
>>> b = [1,3,5,6]
>>> list(set(a) & set(b))
[1, 3, 5]
...
How does java do modulus calculations with negative numbers?
...umbers are in use - some languages use one definition and some the other.
If you want to get a negative number for negative inputs then you can use this:
int r = x % n;
if (r > 0 && x < 0)
{
r -= n;
}
Likewise if you were using a language that returns a negative number on a neg...
One-line list comprehension: if-else variants
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x if y else z is the syntax for the expression you're returning for each element. Thus you need:
[ x if x%2 else x*100 for x in range(1, 10) ]
The confusion arises from the fact you're using a filter in the first example, bu...
Elegant ways to support equivalence (“equality”) in Python classes
...(1)
n1 == n2 # False -- oops
So, Python by default uses the object identifiers for comparison operations:
id(n1) # 140400634555856
id(n2) # 140400634555920
Overriding the __eq__ function seems to solve the problem:
def __eq__(self, other):
"""Overrides the default implementation"""
if...
not None test in Python [duplicate]
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if val is not None:
# ...
is the Pythonic idiom for testing that a variable is not set to None. This idiom has particular uses in the case of declaring keyword functions with default parameters. is tests identity in Pyt...
Divide a number by 3 without using *, /, +, -, % operators
...gt;> 2, sum);
num = add(num >> 2, num & 3);
}
if (num == 3)
sum = add(sum, 1);
return sum;
}
As Jim commented this works, because:
n = 4 * a + b
n / 3 = a + (a + b) / 3
So sum += a, n = a + b, and iterate
When a == 0 (n < 4), sum += floor(n / 3); i....
Javascript - remove an array item by value [duplicate]
...,3,56,6,8,90],
id_tag = 90,
position = tag_story.indexOf(id_tag);
if ( ~position ) tag_story.splice(position, 1);
P.S. For an explanation of that cool ~ tilde shortcut, see this post:
Using a ~ tilde with indexOf to check for the existence of an item in an array.
Note: IE < 9 does ...
How to use if - else structure in a batch file?
I have a question about if - else structure in a batch file. Each command runs individually, but I couldn't use "if - else" blocks safely so these parts of my programme doesn't work. How can I do make these parts run? Thank you.
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Pandas conditional creation of a series/dataframe column
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If you only have two choices to select from:
df['color'] = np.where(df['Set']=='Z', 'green', 'red')
For example,
import pandas as pd
import numpy as np
df = pd.DataFrame({'Type':list('ABBC'), 'Set':list('ZZXY')})
df['col...