Tag：numerical value
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Time：2021-1-22
numerical calculation 1. Overflow and underflow The first problem in numerical computation is numerical overflow and numerical underflow. Overflow refers to the value is very large, overflow is Nan value, and underflow refers to the value is very small, underflow is 0. Numerical overflow is likely to lead to numerical calculation problems, so corresponding solutions […]
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Time：2021-1-15
1. TRUNC function The truncation function can intercept both dates and numbers Select TRUNC (sysdate) from dual; — 07-jun-20 Return yesterday’s date select TRUNC (sysdate-1) from dual; Return to the first day of the month select TRUNC (sysdate, ‘mm’) from dual; — 01-jun-20 Return to the three writing methods of the first day of the […]
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Time：2021-1-6
Getting several common date values with SQL statements —Last week SELECT TO_CHAR(TRUNC(SYSDATE, ‘IW’) – 7, ‘yyyymmdd’) FROM DUAL SELECT TO_CHAR(TRUNC(SYSDATE, ‘IW’) – 1, ‘yyyymmdd’) FROM DUAL —This week SELECT TO_CHAR(TRUNC(SYSDATE, ‘IW’) , ‘yyyymmdd’) FROM DUAL SELECT TO_CHAR(TRUNC(SYSDATE, ‘IW’) + 6, ‘yyyymmdd’) FROM DUAL —The first and last days of last month select trunc(add_months(sysdate, -1), ‘mm’) […]
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Time：2021-1-2
Enumeration is a data type often used in programs. Using enumeration can make the code more readable, extensible and easier to write. At the same time, enumeration is also a strong type to enhance the robustness of the program. For example, to distinguish colors, when enumeration is not used, a convention may be made: define […]
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Time：2020-12-19
In the use of computers, we often encounter system prompts, one of the most common tips is that the minimum virtual memory is too low, so when you encounter XP prompt that the minimum virtual memory value is too low, how to solve it? In fact, it is very simple, we just need to change […]
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Time：2020-12-18
When I look at the lexical analysis part of lua, I can see thatlislalphaThe definition of this macro, from the name, means “judge whether it is a letter”.In the lctype. H file, other macros are defined (for judgment) #define ALPHABIT 0 #define DIGITBIT 1 #define PRINTBIT 2 #define SPACEBIT 3 #define XDIGITBIT 4 #define testprop(c,p) […]
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Time：2020-12-10
Today, I will share with you a pie chart function completed by myself in the previous project. This pie chart is also reformed on the basis of predecessors.Link description1. The pie chart can be rotated after clicking the operation to rotate the selected area to the bottom, and the selected data will be displayed by […]
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Time：2020-11-22
Number type Numerical type, which is usually used to store values, is the most commonly used variable type;The numeric types in Python include the following types:Integer、Long integer、Boolean、Double-precision floating、Complex number。 IntegerPS novice note: many people in the process of learning Python will encounter a variety of vexed questions, no one answers easy to give up. For […]
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Time：2020-11-15
timers and time management Time can be divided into relative and absolute time. When a process runs after 5 seconds, the current time of day (i.e. wall time) is absolute time. The absolute time is usually used when interacting with users. The system timer goes off (often called hitting or popping) at a preprogrammed frequency, […]
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Time：2020-11-12
This article starts in Nuggets: Address: 3 minutes to master 20 practical tips in JS development preface Daily development, we may need to write a lot of JS code, the following development tips can help you. Words not much, directly on the code! String technique Format the thousandth ‘10000000.00’.replace(/(?!^)(?=(\d{3})+\.)/g, ‘,’); // “10,000,000.00” ‘10000000.00’.replace(/\B(?=(\d{3})+\.)/g, ‘,’); // […]
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Time：2020-11-10
JS data type conversion and literal 1. Convert to string mode explain example toString() Convert to string var num=1;alert(num.toString()) String() cast Convert to string var num=1;alert(String(num)) Plus concatenated string And string concatenation results in strings Var num=1; alert (num+’I am a string’) Note: a third conversion method is recommended, also known asImplicit transformation。 2. Convert […]
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Time：2020-10-28
Transact SQL language is a programming language provided by SQL server for users. It is the implementation and extension of standard SQL. It has the main characteristics of standard SQL, At the same time, language elements such as variables, operators, functions and process control are added to make it more powerful. 1. Batch processing, […]
