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Convert a character digit to the corresponding integer in C
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As per other replies, this is fine:
char c = '5';
int x = c - '0';
Also, for error checking, you may wish to check isdigit(c) is true first. Note that you cannot completely portably do the same for letters, for example:
char c = 'b';
int x = c - 'a'; // x is now not necessarily 1
Th...
How to initialize all members of an array to the same value in Swift?
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170
Actually, it's quite simple with Swift. As mentioned in the Apple's doc, you can initialize an a...
List comprehension vs map
... map when using exactly the same function:
$ python -mtimeit -s'xs=range(10)' 'map(hex, xs)'
100000 loops, best of 3: 4.86 usec per loop
$ python -mtimeit -s'xs=range(10)' '[hex(x) for x in xs]'
100000 loops, best of 3: 5.58 usec per loop
An example of how performance comparison gets completely r...
Add missing dates to pandas dataframe
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270
You could use Series.reindex:
import pandas as pd
idx = pd.date_range('09-01-2013', '09-30-201...
How to use arguments from previous command?
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By the way, you could have put the echo on the line by selecting argument 0:
Press Alt-0 Alt-Ctrl-y
Edit:
To answer the question you added to your original:
You can press Alt-0 then repeatedly press Alt-. to step through the previous commands (arg 0). Similarly Alt-- then repeating Alt-. would ...
How can I convert an RGB image into grayscale in Python?
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320
How about doing it with Pillow:
from PIL import Image
img = Image.open('image.png').convert('LA...
“x not in y” or “not x in y”
... 'ham' not in 'spam and eggs'
>>> dis.dis(notin)
2 0 LOAD_CONST 1 ('ham')
3 LOAD_CONST 2 ('spam and eggs')
6 COMPARE_OP 7 (not in)
9 POP_TOP
10 LOAD_CONST ...
Java regular expression OR operator
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edited Jan 9 '10 at 0:57
answered Jan 9 '10 at 0:46
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Boolean literals in PowerShell
...ts are true, for example. null, empty strings, empty arrays and the number 0 are false.
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How do you validate a URL with a regular expression in Python?
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answered May 6 '09 at 1:09
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