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Replacing blank values (white space) with NaN in pandas
...0.814772, 'baz', ' '],
[-0.222552, ' ', 4],
[-1.176781, 'qux', ' '],
], columns='A B C'.split(), index=pd.date_range('2000-01-01','2000-01-06'))
# replace field that's entirely space (or empty) with NaN
print(df.replace(r'^\s*$', np.nan, regex=True))
Produces:
...
How to elegantly check if a number is within a range?
...
There are a lot of options:
int x = 30;
if (Enumerable.Range(1,100).Contains(x))
//true
if (x >= 1 && x <= 100)
//true
Also, check out this SO post for regex options.
...
Android ImageView Zoom-in and Zoom-Out
...
Make two java classes
Zoom class
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
public class Zoom extend...
python plot normal distribution
...tats as stats
import math
mu = 0
variance = 1
sigma = math.sqrt(variance)
x = np.linspace(mu - 3*sigma, mu + 3*sigma, 100)
plt.plot(x, stats.norm.pdf(x, mu, sigma))
plt.show()
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improve th...
Average of 3 long integers
...s, so you 'lose' the remainder), and then divides the remainder:
long n = x / 3
+ y / 3
+ z / 3
+ ( x % 3
+ y % 3
+ z % 3
) / 3
Note that the above sample does not always work properly when having one or more negative values.
As dis...
Why use double indirection? or Why use pointers to pointers?
When should a double indirection be used in C? Can anyone explain with a example?
18 Answers
...
Reading from text file until EOF repeats last line [duplicate]
...he following C++ code uses a ifstream object to read integers from a text file (which has one number per line) until it hits EOF . Why does it read the integer on the last line twice? How to fix this?
...
“for loop” with two variables? [duplicate]
...ested for loop, use:
import itertools
for i, j in itertools.product(range(x), range(y)):
# Stuff...
If you just want to loop simultaneously, use:
for i, j in zip(range(x), range(y)):
# Stuff...
Note that if x and y are not the same length, zip will truncate to the shortest list. As @a...
variable === undefined vs. typeof variable === “undefined”
...for comparison can throw an error whereas a typeof check never will.
For example, the following is used in IE for parsing XML:
var x = new ActiveXObject("Microsoft.XMLDOM");
To check whether it has a loadXML method safely:
typeof x.loadXML === "undefined"; // Returns false
On the other hand:
...
Static variable inside of a function in C
...ope.
The scope of variable is where the variable name can be seen. Here, x is visible only inside function foo().
The lifetime of a variable is the period over which it exists. If x were defined without the keyword static, the lifetime would be from the entry into foo() to the return from foo();...