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Check if a given key already exists in a dictionary and increment it
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iOS UIImagePickerController result image orientation after upload
I am testing my iPhone application on an iOS 3.1.3 iPhone. I am selecting/capturing an image using a UIImagePickerController :
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How is “int* ptr = int()” value initialization not illegal?
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int() is a constant expression with a value of 0, so it's a valid way of producing a null poin...
二维码的生成细节及原理 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...说一下二维码一共有40个尺寸。官方叫版本Version。Version 1是21 x 21的矩阵，Version 2是 25 x 25的矩阵，Version 3是29的尺寸，每增加一个version，就会增加4的尺寸，公式是：(V-1)*4 + 21（V是版本号） 最高Version 40，(40-1)*4+21 = 177，所以最高...
How to concatenate two MP4 files using FFmpeg?
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How can I implode an array while skipping empty array items?
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212
You can use array_filter():
If no callback is supplied, all entries of input equal to FALSE...
Aren't Python strings immutable? Then why does a + “ ” + b work?
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First a pointed to the string "Dog". Then you changed the variable a to point at a new string...
How to delete an element from an array in C#
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How to select a single field for all documents in a MongoDB collection?
In my MongoDB, I have a student collection with 10 records having fields name and roll . One record of this collection is:
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Pandas count(distinct) equivalent
...()
Example:
In [2]: table
Out[2]:
CLIENTCODE YEARMONTH
0 1 201301
1 1 201301
2 2 201301
3 1 201302
4 2 201302
5 2 201302
6 3 201302
In [3]: table.groupby('YEARMONTH').CLIENTCODE.nunique()
Out[3...