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What are the special dollar sign shell variables?
...ipeline exit status.
$! is the PID of the most recent background command.
$0 is the name of the shell or shell script.
Most of the above can be found under Special Parameters in the Bash Reference Manual. There are all the environment variables set by the shell.
For a comprehensive index, please ...
How assignment works with Python list slice?
...g two distinct operation that use very similar syntax:
1) slicing:
b = a[0:2]
This makes a copy of the slice of a and assigns it to b.
2) slice assignment:
a[0:2] = b
This replaces the slice of a with the contents of b.
Although the syntax is similar (I imagine by design!), these are two di...
Regular expression to match non-ASCII characters?
...
This should do it:
[^\x00-\x7F]+
It matches any character which is not contained in the ASCII character set (0-127, i.e. 0x0 to 0x7F).
You can do the same thing with Unicode:
[^\u0000-\u007F]+
For unicode you can look at this 2 resources:
...
Converting JSON String to Dictionary Not List
...with a dictionary inside. You can access your dictionary by accessing item 0 in the list, as shown below:
json1_data = json.loads(json1_str)[0]
Now you can access the data stored in datapoints just as you were expecting:
datapoints = json1_data['datapoints']
I have one more question if an...
Border length smaller than div width?
...
You can use pseudoelements. E.g.
div {
width : 200px;
height : 50px;
position: relative;
z-index : 1;
background: #eee;
}
div:before {
content : "";
position: absolute;
left : 0;
bottom : 0;
height : 1px;
width : 50%; /* or 100...
add a string prefix to each value in a string column using Pandas
...['col'].astype(str)
Example:
>>> df = pd.DataFrame({'col':['a',0]})
>>> df
col
0 a
1 0
>>> df['col'] = 'str' + df['col'].astype(str)
>>> df
col
0 stra
1 str0
share
...
How do I scale a stubborn SVG embedded with the tag?
...dd the following attributes:
preserveAspectRatio="xMinYMin meet"
viewBox="0 0 {width} {height}"
Replace {width} and {height} with some defaults for the viewBox. I used the values from the "width" and "height" attributes of the SVG tag and it seemed to work.
Save the SVG and it should now scale a...
Divide a number by 3 without using *, /, +, -, % operators
... x = t;
}
return y;
}
int divideby3(int num)
{
int sum = 0;
while (num > 3) {
sum = add(num >> 2, sum);
num = add(num >> 2, num & 3);
}
if (num == 3)
sum = add(sum, 1);
return sum;
}
As Jim commented this works, because:...
Too many 'if' statements?
...
600
If you cannot come up with a formula, you can use a table for such a limited number of outcomes...
Reduce left and right margins in matplotlib plot
...E.g.
import matplotlib.pyplot as plt
import numpy as np
data = np.arange(3000).reshape((100,30))
plt.imshow(data)
plt.savefig('test.png', bbox_inches='tight')
Another way is to use fig.tight_layout()
import matplotlib.pyplot as plt
import numpy as np
xs = np.linspace(0, 1, 20); ys = np.sin(xs)
...