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Why can't I use a list as a dict key in python?
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11 Answers
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jQuery map vs. each
...ion you can potentially waste a lot of memory.
For example:
var items = [1,2,3,4];
$.each(items, function() {
alert('this is ' + this);
});
var newItems = $.map(items, function(i) {
return i + 1;
});
// newItems is [2,3,4,5]
You can also use the map function to remove an item from an array...
How to use Active Support core extensions
I have Active Support 3.0.3 installed and Rails 3.0.3 with Ruby 1.8.7.
5 Answers
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How do you match only valid roman numerals with a regular expression?
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16 Answers
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Extracting numbers from vectors of strings
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11 Answers
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How to create custom easing function with Core Animation?
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// this should be a function that takes a time value between
// 0.0 and 1.0 (where 0.0 is the beginning of the animation
// and 1.0 is the end) and returns a scale factor where 0.0
// would produce the starting value and 1.0 would produce the
// ending value
typedef double (^KeyframeParametric...
bash/fish command to print absolute path to a file
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591
Use realpath
$ realpath example.txt
/home/username/example.txt
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Best way to merge two maps and sum the values of same key?
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15 Answers
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Passing parameters to JavaScript files
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14 Answers
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Relative frequencies / proportions with dplyr
...se(n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That mak...