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Python: Append item to list N times
...
For immutable data types:
l = [0] * 100
# [0, 0, 0, 0, 0, ...]
l = ['foo'] * 100
# ['foo', 'foo', 'foo', 'foo', ...]
For values that are stored by reference and you may wish to modify later (like sub-lists, or dicts):
l = [{} for x in range(100)]
(Th...
Format output string, right alignment
...r.format syntax:
line_new = '{:>12} {:>12} {:>12}'.format(word[0], word[1], word[2])
And here's how to do it using the old % syntax (useful for older versions of Python that don't support str.format):
line_new = '%12s %12s %12s' % (word[0], word[1], word[2])
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Test whether string is a valid integer
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[[ $var =~ ^-?[0-9]+$ ]]
The ^ indicates the beginning of the input pattern
The - is a literal "-"
The ? means "0 or 1 of the preceding (-)"
The + means "1 or more of the preceding ([0-9])"
The $ indicates the end of the input pattern
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How to use shared memory with Linux in C
...lains their purpose.
return mmap(NULL, size, protection, visibility, -1, 0);
}
The following is an example program that uses the function defined above to allocate a buffer. The parent process will write a message, fork, and then wait for its child to modify the buffer. Both processes can read a...
COUNT DISTINCT with CONDITIONS
...count(distinct tag) as tag_count,
count(distinct (case when entryId > 0 then tag end)) as positive_tag_count
from
your_table_name;
The first count(distinct...) is easy.
The second one, looks somewhat complex, is actually the same as the first one, except that you use case...when clause. In ...
Javascript fuzzy search that makes sense
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10 Answers
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Active
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How to sort an array in Bash
...ed and see!
– antak
Oct 19 '15 at 9:04
3
Very nice. Could you explain for the average bash user h...
What's the UIScrollView contentInset property for?
...enclosing scroll view.
Obj-C
aScrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 7.0);
Swift 5.0
aScrollView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 7.0)
Here's a good iOS Reference Library article on scroll views that has an informative screenshot (fig 1-3) - I'll rep...
Remove duplicated rows using dplyr
...r below:
library(dplyr)
set.seed(123)
df <- data.frame(
x = sample(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_number(z) == 1)
## Source: local data fr...
Build an ASCII chart of the most commonly used words in a given text [closed]
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LabVIEW 51 nodes, 5 structures, 10 diagrams
Teaching the elephant to tap-dance is never pretty. I'll, ah, skip the character count.
The program flows from left to right:
sha...