在用mongo进行查询时，$exists表示是否document是否包含这个field，即使field的value为null也算是包含。$exists
Syntax: { field: { $exists: } }
When is true, $exists matches the documents that contain the field, including documents w...
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其他好文 时间：
2014-08-24 11:43:02
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187
Hadoop HDFS文件常用操作及注意事项1.Copy a file from the local file system to HDFSThe srcFile variable needs to contain the full name (path + file name) of the fi...
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其他好文 时间：
2014-08-21 12:50:04
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224
AssetBundles are files which you can export from Unity to contain assets of your choice. These files use a proprietary compressed format and can be loaded on demand in your application. This allows...
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其他好文 时间：
2014-08-21 11:46:04
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1.Copy a file from the local file system to HDFSThe srcFile variable needs to contain the full name (path + file name) of the file in the local file s...
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其他好文 时间：
2014-08-21 11:24:34
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242
Given a collection of integers that might contain duplicates, S, return all possible subsets.Note:Elements in a subset must be in non-descending order...
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其他好文 时间：
2014-08-20 19:37:12
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175
Atlantis
Time Limit: 1000MS
Memory Limit: 10000K
Total Submissions: 17464
Accepted: 6654
Description
There are several ancient Greek texts that contain descriptions...
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其他好文 时间：
2014-08-17 17:06:02
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297
Description
A common pastime for poker players at a poker table is to shuffle stacks of chips. Shuffling chips is performed by starting with two stacks of poker chips, S1 and S2, each stack contain...
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其他好文 时间：
2014-08-16 23:51:21
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505
Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n).For example, S = "ADOBECOD...
Given a collection of integers that might contain duplicates,S, return all possible subsets.Note:Elements in a subset must be in non-descending order....
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其他好文 时间：
2014-08-15 21:08:29
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212
Minimum Window SubstringGiven a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n).Fo...
