Differences in operator precedence between PHP and JavaScript

Source: Internet
Author: User
The two priorities are the same, and the comparison (comparision) and Assignment (Assignment) operations are slightly different. The comparison operator has a, <, >=, and so on, the assignment operator has =, + =, *=, and so on.

The comparison operator in JS has a higher precedence than the assignment operator. So foo = 1 < 2 result Foo = false;

In PHP, in turn, the assignment operator takes precedence over the comparison operator. So foo = 1 < 2 result foo = 1, the expression is false. To achieve the same result as above, enclose the parentheses

Foo = (1 < 2)

Attached: full operator precedence for PHP and JavaScript

Js

The following table is ordered from highest (+) to lowest (0) precedence.

Precedence Operator Type associativity Individual Operators
19 Grouping N/A ( … )
18 Member Access Left-to-right … . …
Computed Member Access Left-to-right … [ … ]
New (with argument list) N/A new … ( … )
17 Function Call Left-to-right … ( … )
New (without argument list) Right-to-left new …
16 Postfix Increment N/A … ++
Postfix Decrement N/A … --
15 Logical not Right-to-left ! …
Bitwise not Right-to-left ~ …
Unary Plus Right-to-left + …
Unary negation Right-to-left - …
Prefix Increment Right-to-left ++ …
Prefix Decrement Right-to-left -- …
typeof Right-to-left typeof …
void Right-to-left void …
Delete Right-to-left delete …
14 exponentiation Right-to-left … ** …
Multiplication Left-to-right … * …
Division Left-to-right … / …
Remainder Left-to-right … % …
13 Addition Left-to-right … + …
Subtraction Left-to-right … - …
12 Bitwise left Shift Left-to-right … << …
Bitwise Right Shift Left-to-right … >> …
Bitwise Unsigned Right Shift Left-to-right … >>> …
11 Less Than Left-to-right … < …
Less Than Or Equal Left-to-right … <= …
Greater Than Left-to-right … > …
Greater Than Or Equal Left-to-right … >= …
Inch Left-to-right … in …
instanceof Left-to-right … instanceof …
10 Equality Left-to-right … == …
Inequality Left-to-right … != …
Strict Equality Left-to-right … === …
Strict inequality Left-to-right … !== …
9 Bitwise and Left-to-right … & …
8 Bitwise XOR Left-to-right … ^ …
7 Bitwise OR Left-to-right … | …
6 Logical and Left-to-right … && …
5 Logical OR Left-to-right … || …
4 Conditional Right-to-left … ? … : …
3 Assignment Right-to-left … = …
… += …
… -= …
… **= …
… *= …
… /= …
… %= …
… <<= …
… >>= …
… >>>= …
… &= …
… ^= …
… |= …
2 Yield Right-to-left yield …
1 Spread N/A ......
0

Php

Operator Precedence
associativity Operators Additional Information
Non-associative Clone new Clone andnew
Left [ Array ()
Right ** Arithmetic
Right + +--~ (int) (float) (string) (array) (object) (BOOL) @ Types Andincrement/decrement
Non-associative instanceof Types
Right ! Logical
Left * / % Arithmetic
Left + - . Arithmetic andstring
Left << >> Bitwise
Non-associative < <= > >= Comparison
Non-associative = = = = = = =!== <> <=> Comparison
Left & Bitwise andreferences
Left ^ Bitwise
Left | Bitwise
Left && Logical
Left || Logical
Right ?? Comparison
Left ? : Ternary
Right = + = = *= **=/=. =%= &= |= ^= <<= >>= Assignment
Left and Logical
Left Xor Logical
Left Or Logical

The above describes the PHP and JavaScript operator precedence differences, including aspects of the content, I hope that the PHP tutorial interested in a friend helpful.

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