true true false

using PHP functions to $x compare variables An expression GetType () empty () is_null () isset () boolean : if ($x) $x = ""; string true false

The operator is a symbol that tells the compiler to perform a specific mathematical or logical operation. The R language has rich built-in operators and provides the following types of operators.Operator type Arithmetic operators

I. What is JSON1. JSON is the abbreviation for JavaScript Object notation, which is a data interchange format2. Essence is a string, is the string representation of the JS object3. Similar to the dictionary in Python, but there are some grammatical

UrlEncode and UrlDecode When the URL contains Chinese or the parameter contains Chinese, the Chinese or special characters (/, &) need to be encoded for conversion.The essence of UrlEncode: Convert the string to GBK encoding, and then replace

Describe conditional logic as an array operationNumpy.where () is an expression of three-mesh operation1 in [the]: Xarr = Np.array ([1.1,1.2,1.3,1.4,1.5])23 in []: Yarr = Np.array ([ 2.1,2.2,2.3,2.4,2.5])45 in [approx]: Condi = Np.array ([True,false,

To generate a file name for a graphics file in the R language, the prefix is Fitbit, followed by the month after, plus ". jpg", first not Baidu, tried other languages similar grammar, not a viable:In C #: "Fitbit" + month + ". jpg"VB: "Fitbit" &

First look at the matrix. The result of a operation1>>> A=mat ([[1,2,3],[2,3, 0]]);2>>>a3Matrix ([[[1, 2, 3],4[2, 3, 0]])5>>>A.A6Array ([[[1, 2, 3],7[2, 3, 0]])8>>>shape (a)9(2, 3)Ten>>>shape (A.A) One(2, 3) A>>>type (a) -class

First, Python support for JSONStarting with python2.6, JSON support has been added to the Python standard library, and it is only necessary to manipulate the JSON import json .Second, the Python object is converted into a JSON stringWhen you convert

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is based on a subset of ECMAScript.The JSON module can be used to encode JSON data in Python3, which contains two functions: json.dumps (): encodes the data.

After we have successfully written the HelloWorld, have you ever wondered what parts of Java programs are made up of? This is actually the chapter to study the content, this section first study the keywords and identifiers, in the identifier we will

Structure of the 1.Hash tableFirst, allow us to take a moment to introduce the hash table briefly.1. What is a hash tableA hash table is a two-dimensional structure. Attach a picture and we'll start a lengthy speech.As shown, the left side is an

1. Variable naming (1) Variable names should not be proud of a short coincidenceThe variable name on the left is not very clear, the code extensibility is not good, once the code needs to add functionality, it is easy to appear obj1, Obj2, obj3 this

Structure of the 1.Hash tableFirst, allow us to take a moment to introduce the hash table briefly.1. What is a hash tableHash table is a two-dimensional structure, the management of a pair of such key-value pairs, the structure of the hash table as

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is based on a subset of ECMAScript.1, Json.dumps () and json.loads () are JSON format processing functions (so to understand, JSON is a string) The Json.dumps ()

ObjectiveRecently things are not many, want to write some technical articles to share to everyone, but also for a period of time to the fragmentation of the knowledge of the acceptance of a comb, so-called write clearly can be said clearly, clear to

JSON functionsUse JSON functions to import the JSON library: importJSON. function Description Json.dumps Encode a Python object as a JSON string Json.loads Decodes an encoded JSON

Java Natural Pride Series-3operator (cont.)1. logical operators (cont.)logical operators are used to connect Boolean Types of Expressions1) with symbols: &true&true=true;true&false=false;false&true=false;false&false=false;2) or symbol: |true| true

Data type Overall Division Scalar type: int, float, string, bool Composite type: Array, object Special type: null, resouce Integer type int, integer3 integer notation Decimal notation: 123: $n 1 = 123;

In JavaScript, the logical OR operator uses the | | Said|| Bfalse;The following truth table describes the behavior of the logical AND operator: Number of Operations 1 Number of Operations 2 Results True

Isset determine if the variable already exists empty determines whether the variable is null or is 0is_null to determine if the variable is nullable Variable Empty Is_null Isset $a = "