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Test whether a glob has any matches in bash
If I want to check for the existence of a single file, I can test for it using test -e filename or [ -e filename ] .
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Checking if a string array contains a value, and if so, getting its position
...4" };
string value = "text3";
int pos = Array.IndexOf(stringArray, value);
if (pos > -1)
{
// the array contains the string and the pos variable
// will have its position in the array
}
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Definition of a Balanced Tree
I am just wondering if someone might be able to clarify the definition of a balanced tree for me. I have that "a tree is balanced if each sub-tree is balanced and the height of the two sub-trees differ by at most one.
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How do I make a batch file terminate upon encountering an error?
I have a batch file that's calling the same executable over and over with different parameters. How do I make it terminate immediately if one of the calls returns an error code of any level?
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Detect if a jQuery UI dialog box is open
I am using a jQuery UI dialog. If it is open, I want to do one thing. If it is closed, I want to do another.
5 Answers
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Efficient way to remove keys with empty strings from a dict
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Python 2.X
dict((k, v) for k, v in metadata.iteritems() if v)
Python 2.7 - 3.X
{k: v for k, v in metadata.items() if v is not None}
Note that all of your keys have values. It's just that some of those values are the empty string. There's no such thing as a key in a dict w...
Remove all values within one list from another list? [duplicate]
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>>> a = range(1, 10)
>>> [x for x in a if x not in [2, 3, 7]]
[1, 4, 5, 6, 8, 9]
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Checking for empty queryset in Django
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if not orgs:
# Do this...
else:
# Do that...
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Find the index of a dict within a list, by matching the dict's value
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tom_index = next((index for (index, d) in enumerate(lst) if d["name"] == "Tom"), None)
# 1
If you need to fetch repeatedly from name, you should index them by name (using a dictionary), this way get operations would be O(1) time. An idea:
def build_dict(seq, key):
return dic...
What .NET collection provides the fastest search
... answer to "What is the fastest searchable collection" depends on your specific data size, ordered-ness, cost-of-hashing, and search frequency.
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