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Determine the number of NA values in a column
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321
You're over-thinking the problem:
sum(is.na(df$col))
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What's the difference between a proxy server and a reverse proxy server? [closed]
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3000
The previous answers were accurate, but perhaps too terse.
I will try to add some examples.
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What's the Android ADB shell “dumpsys” tool and what are its benefits?
... adb shell dumpsys wifi
Output:
Wi-Fi is enabled
Stay-awake conditions: 3
Internal state:
interface tiwlan0 runState=Running
SSID: XXXXXXX BSSID: xx:xx:xx:xx:xx:xx, MAC: xx:xx:xx:xx:xx:xx, Supplicant state: COMPLETED, RSSI: -60, Link speed: 54, Net ID: 2, security: 0, idStr: null
ipaddr 192.168....
Explaining Apache ZooKeeper
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436
In a nutshell, ZooKeeper helps you build distributed applications.
How it works
You may descr...
Determining Referer in PHP
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93
The REFERER is sent by the client's browser as part of the HTTP protocol, and is therefore unrel...
How to convert PascalCase to pascal_case?
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31 Answers
31
Active
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How do I make a placeholder for a 'select' box?
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34 Answers
34
Active
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Select tableview row programmatically
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edited Feb 15 '18 at 7:43
Pang
8,2181717 gold badges7373 silver badges111111 bronze badges
answered Ja...
How to prevent multiple instances of an Activity when it is launched with different Intents
...ork around for market launches. See https://issuetracker.google.com/issues/36907463
// for more details. Essentially, the market launches the main activity on top of other activities.
// we never want this to happen. Instead, we check if we are the root and if not, we finish.
if (!isTaskRoot()) {
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Maintain/Save/Restore scroll position when returning to a ListView
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633
Try this:
// save index and top position
int index = mList.getFirstVisiblePosition();
View v =...