大约有 8,900 项符合查询结果（耗时：0.0168秒） [XML]
DISTINCT for only one column
...d@cyberdyne.com
125 || SARAH CONNOR ||s.connor@skynet.com
Remember to index the columns you select and the distinct column must have not numeric data all in upper case or in lower case, or else it won't work.
This will work with only one registered mail as well.
Happy coding!!!
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Why should I use Deque over Stack?
...ncy: Stack extends the Vector class, which allows you to access element by index. This is inconsistent with what a Stack should actually do, which is why the Deque interface is preferred (it does not allow such operations)--its allowed operations are consistent with what a FIFO or LIFO data structur...
How to implement classic sorting algorithms in modern C++?
...re elementary sorting algorithms , such as selection sort, insertion sort, quick sort, merge sort, or heap sort.
2 Answers
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Django filter versus get for single object?
...ple:
try:
p = Article.objects.order_by('title', 'pub_date')[0]
except IndexError:
p = None
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Singular or plural controller and helper names in Rails
...g should be plural and came case. e.g: :rails generate controller Dogs new index create delete destroy edit" ??
– BKSpurgeon
Oct 25 '15 at 5:48
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How to make a always full screen?
...0%;
left: 0;
top: 0;
background: rgba(51,51,51,0.7);
z-index: 10;
}
</style>
</head>
<body>
<div class='overlay'>Selectable text</div>
<p> This paragraph is located below the overlay, and cannot be selected because of that :)</...
For each row in an R dataframe
... up with (x) is a vector. This is why the above example has to use numeric indexes; the by() approach gives you a data.frame, which makes your code more robust.
– Darren Cook
Dec 19 '11 at 5:20
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Get the client IP address using PHP [duplicate]
...alse if the variable isn't set, where $_SERVER will error with "undefined index" if the variable isn't set.
– Michael
Feb 7 '14 at 1:45
4
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Call a controller function from a directive without isolated scope in AngularJS
...et()
But you can also use array notation:
some_obj['greet']
Note how the index value is a string. So, in your directive you can simply do this:
link: function (scope, element, attrs) {
element.bind('click', function (e) {
if (confirm(attrs.confirm)) {
var func_str = attrs.con...
How to declare an array in Python?
...nit with values (can contain mixed types)
arr = [1, "eels"]
# get item by index (can be negative to access end of array)
arr = [1, 2, 3, 4, 5, 6]
arr[0] # 1
arr[-1] # 6
# get length
length = len(arr)
# supports append and insert
arr.append(8)
arr.insert(6, 7)
Theoretical answer
Under the hood...