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Running multiple commands in one line in shell
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824
You are using | (pipe) to direct the output of a command into another command. What you are loo...
Creating Multifield Indexes in Mongoose / MongoDB
...For your case it would be something like:
mySchema.index({field1: 1, field2: 1}, {unique: true});
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How to define different dependencies for different product flavors
... }
dependencies {
classpath 'com.android.tools.build:gradle:1.2.3'
}
}
apply plugin: 'com.android.application'
repositories {
mavenCentral()
}
android {
compileSdkVersion 22
buildToolsVersion "22.0.1"
defaultConfig {
minSdkVersion 10
targetSdkVersi...
Android:What is difference between setFlags and addFlags for intent
... flags look like this: 1, 10, 100, 1000, etc... (which in this case are 1, 2, 4, 8). So, what addFlags does is appending the integer you pass using the | operator.
// example...
// value of flags: 1
intent.setFlags(2|4);
// now flags have this value: 110
intent.addFlags(8);
// now flags have thi...
Append a NumPy array to a NumPy array
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234
In [1]: import numpy as np
In [2]: a = np.array([[1, 2, 3], [4, 5, 6]])
In [3]: b = np.array...
List comprehension rebinds names even after scope of comprehension. Is this right?
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172
List comprehensions leak the loop control variable in Python 2 but not in Python 3. Here's Guid...
Get Unix Epoch Time in Swift
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162
You can simply use NSDate's timeIntervalSince1970 function.
let timeInterval = NSDate().timeIn...
How to install latest version of git on CentOS 7.x/6.x
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362
You can use WANDisco's CentOS repository to install Git 2.x: for CentOS 6, for CentOS 7
Instal...
Assign pandas dataframe column dtypes
...ated in 0.17)
df = pd.DataFrame({'x': {0: 'a', 1: 'b'}, 'y': {0: '1', 1: '2'}, 'z': {0: '2018-05-01', 1: '2018-05-02'}})
df.dtypes
x object
y object
z object
dtype: object
df
x y z
0 a 1 2018-05-01
1 b 2 2018-05-02
You can apply these to each column you want to co...
Boolean operators && and ||
...rter ones are vectorized, meaning they can return a vector, like this:
((-2:2) >= 0) & ((-2:2) <= 0)
# [1] FALSE FALSE TRUE FALSE FALSE
The longer form evaluates left to right examining only the first element of each vector, so the above gives
((-2:2) >= 0) && ((-2:2) <...