Summary of articles about conversions

The problem is that both integers and floating-point numbers in JavaScript belong to the Number data type (one of the simple data types). We often find that the result of printing a floating-point number like 1.0 is 1 instead of 1.0, because the memory space in which the floating-point is saved is twice times the integer value, so ECMAScript will lose no time in converting floating-point numbers to integers. This situation is a bit uncomfortable for obsessive-compulsive patients, but it's not a big mistake at all, and the next thing is scary. For example, when we calculate 0.1 plus 0.2, it's output is not 0.3, but 0.3000000000000004. What the fuck?! Have you ever felt the challenge of the world view for the first time in a child's shoes? The reason why quickly turn over books to save your soul and body, found the book is impressively written: Ecmascrip is based on IEEE754 numerical floating point calculation if you don't know what IEEE754 is, just point to me, this numerical method will save the value as a binary and then calculate, Because floating-point numbers are infinite when they are expressed in binary terms, they are

1. A detailed introduction to PHP knowledge points

Summary: Problems in JavaScript both integers and floating-point numbers belong to the Number data type (one of the simple data types). We often find that the result of printing a floating-point number like 1.0 is 1 instead of 1.0, because the memory space in which the floating-point is saved is twice times the integer value, so ECMAScript will lose no time in converting floating-point numbers to integers.   This situation is a bit uncomfortable for obsessive-compulsive patients, but at least it's not a big mistake, and then it's scary. For example, when we calculate 0.1 plus 0.2, it's output knot ...

2.10 recommended courses on data cleansing

Introduction: To do a data cleaning when the code to write, do the data processing, the original file in the process of processing needs to convert to a certain format,  raw file data: 123.txt1,3,42,3,51,2,3,52,5 use Python to convert to a two-dimensional list: #!/ Usr/bin/env python#coding=utf-8def loaddataset ():     &n ...

3. A detailed description of the two-dimensional list

Introduction: To do a data cleaning when the code to write, do the data processing, the original file in the process of processing needs to convert to a certain format,  raw file data: 123.txt1,3,42,3,51,2,3,52,5 use Python to convert to a two-dimensional list: #!/ Usr/bin/env python#coding=utf-8def loaddataset ():     &n ...

4. Summary of BBS design based on MySQL

Introduction: 6. Bbsd and cq66 server-side transformation   bbsd, the user's module should be relatively good change, as long as will write. The operation of the passwd file is replaced by the member function of the Usermanage class that operates the database, but it is possible to determine what data changes to call and which function to invoke. The consistency of concurrency operation is ensured by the lock function of database, and MySQL should support this kind of lock. The article may be more troublesome, but also the original operation of the file into the operation of the database Boardmanage class ...

5. A detailed description of the strong

Introduction: Concat () joins elements into an array join () converts all elements of an array into strings and joins together splice () inserts, deletes, replaces array elements push () adds elements to the end of the array pop () moves the last element of the divisor group shift () Move the first element of the divisor group Unshift () in the array header insert element slice () returns part of the array every () tests whether the assertion function is true for each array element some () tests if at least one array element can make the assertion function true fore ...

6. A detailed description of the dataset, String, DataTable

About: /// <summary>    ///  Provides methods to convert other types to json    /// </summary> & Nbsp;  public st

7. How does a formatted string work? Summarize formatting string instance usage

About:    The structs in Python are primarily used to handle C structured data, which is converted to Python's string type before being read, and then converted to a structured type of python, such as the tuple (tuple). The common input channel originates from the binary stream of the file or network. 1.struct.pack () and Struct.unpack ()      in the conversion process, the main use of a formatted string (format ...

8. Recommended 10 articles for format requirements

Summary: PHP comes with a function fputcsv can be printed report (EXCEL) functionality. If your report format requirements are not very high, then fputcsv is a good choice. It performs efficiently and does not require a third-party library, which is convenient to use. The above code will generate a CSV file locally, can be opened in Excel, is not very simple. If there is Chinese, after Linux execution, download to the local open will be garbled, then you can use the Iconv function to convert. $list = Array (); $tm ...

9. A detailed description of the catalog method

Summary: 12 basic knowledge commonly used in Python programming: regular expression substitution, traversal of directory methods, list sort by column, de-weight, dictionary sort, dictionary, list, string cross, time object operation, command line argument parsing (getopt), print format output, binary conversion,　　Python calls system commands or scripts, and Python reads and writes files. 1. Regular expression substitution target: Replace overview.gif in string line with other string >>&g ...

10. Recommended for 10 articles on-GBK

Introduction: How to convert data from GB2312 to UTF-8 I used iconv and mb_convert_encoding two functions have tried, and then found that the results are the same, there will be a variety of problems, not where fewer words is a direct error, How can god solve this?------solution--------------------gbk  data into the  utf8  table, just once before inserting  mysql _query (' Set&nbs ...

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