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There are two sorts of logical operators: those that accept and return vectors of any length (elementwise operators: !, |, &, xor()) and those that only evaluate the first element in each argument (&&, ||). The second sort is primarily used as the cond argument to the if function. Logic...

To coerce a variable to a date use the as.Date() function. > x <- as.Date("2016-8-23") > x [1] "2016-08-23" > class(x) [1] "Date" The as.Date() function allows you to provide a format argument. The default is %Y-%m-%d, which is Year-month-day. > ...

Sometimes we want to prepare a context for each test to be run under. The setUp method is run prior to each test in the class. tearDown is run at the end of every test. These methods are optional. Remember that TestCases are often used in cooperative multiple inheritance so you should be careful to...

Pandas uses provides multiple ways to make graphs of the data inside the data frame. It uses matplotlib for that purpose. The basic graphs have their wrappers for both DataFrame and Series objects: Line Plot df = pd.DataFrame({'x': [10, 8, 10, 7, 7, 10, 9, 9], 'y': [6, 4, 5, 5...

str.contains() method can be used to check if a pattern occurs in each string of a Series. str.startswith() and str.endswith() methods can also be used as more specialized versions. In [1]: animals = pd.Series(['cat', 'dog', 'bear', 'cow', 'bird', 'owl', 'rabbit', 'snake']) Check if strings con...

In [1]: ser = pd.Series(['lORem ipSuM', 'Dolor sit amet', 'Consectetur Adipiscing Elit']) Convert all to uppercase: In [2]: ser.str.upper() Out[2]: 0 LOREM IPSUM 1 DOLOR SIT AMET 2 CONSECTETUR ADIPISCING ELIT dtype: object All lowercase: In [3]: ser...

Given the following DataFrame: In [11]: df = pd.DataFrame({'a':[1,1,1,2,2,3],'b':[4,4,5,5,6,7,],'c':[10,11,12,13,14,15]}) In [12]: df.set_index(['a','b'], inplace=True) In [13]: df Out[13]: c a b 1 4 10 4 11 5 12 2 5 13 6 14 3 7 15 You can iterate by any lev...

This example shows how to use column data to set a MultiIndex in a pandas.DataFrame. In [1]: df = pd.DataFrame([['one', 'A', 100], ['two', 'A', 101], ['three', 'A', 102], ...: ['one', 'B', 103], ['two', 'B', 104], ['three', 'B', 105]], ...: columns=['c1'...

It's easier to implement some UDFs on the worksheet if full column references can be passed in as parameters. However, due to the explicit nature of coding, any loop involving these ranges may be processing hundreds of thousands of cells that are completely empty. This reduces your VBA project (and ...

An Option is a data structure that contains either a single value, or no value at all. An Option can be thought of as collections of zero or one elements. Option is an abstract class with two children: Some and None. Some contains a single value, and None contains no value. Option is useful in ex...

You can think of an OperationQueue as a line of tasks waiting to be executed. Unlike dispatch queues in GCD, operation queues are not FIFO (first-in-first-out). Instead, they execute tasks as soon as they are ready to be executed, as long as there are enough system resources to allow for it. Get th...

The Foundation framework provides the Operation type, which represents a high-level object that encapsulates a portion of work that may be executed on a queue. Not only does the queue coordinate the performance of those operations, but you can also establish dependencies between operations, create c...

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public class SignUpActivity extends BaseAppCompatActivity { @BindView(R.id.tIETSignUpEmail) EditText mEditEmail; @BindView(R.id.tIETSignUpPassword) EditText mEditPassword; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCrea...

public class LoginActivity extends BaseAppCompatActivity { @BindView(R.id.tIETLoginEmail) EditText mEditEmail; @BindView(R.id.tIETLoginPassword) EditText mEditPassword; @Override protected void onResume() { super.onResume(); FirebaseUser firebaseUs...

public class ForgotPasswordActivity extends AppCompatActivity { @BindView(R.id.tIETForgotPasswordEmail) EditText mEditEmail; private FirebaseAuth mFirebaseAuth; private FirebaseAuth.AuthStateListener mAuthStateListener; @Override protected void onCreate(Bundle saved...

public class ChangeEmailActivity extends BaseAppCompatActivity implements ReAuthenticateDialogFragment.OnReauthenticateSuccessListener { @BindView(R.id.et_change_email) EditText mEditText; private FirebaseUser mFirebaseUser; @OnClick(R.id.btn_change_email) void onChangeE...

public class ChangePasswordActivity extends BaseAppCompatActivity implements ReAuthenticateDialogFragment.OnReauthenticateSuccessListener { @BindView(R.id.et_change_password) EditText mEditText; private FirebaseUser mFirebaseUser; @OnClick(R.id.btn_change_password) void on...

public class ReAuthenticateDialogFragment extends DialogFragment { @BindView(R.id.et_dialog_reauthenticate_email) EditText mEditTextEmail; @BindView(R.id.et_dialog_reauthenticate_password) EditText mEditTextPassword; private OnReauthenticateSuccessListener mOnReauthenticat...

Java configuration is typically done by applying the @Configuration annotation to a class to suggest that a class contains bean definitions. The bean definitions are specified by applying the @Bean annotation to a method that returns an object. @Configuration // This annotation tells the Applicati...