first 4 digits of visa

#Python练习题 001:4 digits for non-repeating 3-digit numbers#方法一Import Itertoolsres = [][Res.append (i[0]*+ i[1]*Ten + i[2])For IIn Itertools.permutations (range (1,5),3)]Print (res, end =‘,‘)"""ReferenceHttps://www.cnblogs.com/iderek/p/5952126.html"""#方法二For IIn range (1,5): for J in range 1 5): for k in range 1 5): if i!=j and i!=k and j!=k: Res=i*100+j*10+k Print (Res" \t Print () Python3 Exercise

What is the vampire number. A vampire number is a number that has an even number of digits, and can be multiplied by a pair of numbers, and this pair of digits contains the half digits of the product, The number that is selected from the initial number can be sorted arbitrarily. The number ending with two 0 is not allowed, For example, the following numbers ar

1. Native JS Writing !function () { document.getElementById (' Bankcard '). onkeyup = function (event) { var v = this.value; if (/\s{5}/.test (v)) { this.value = v.replace (/\s/g, '). Replace (/(. { 4})/g, "$";} } ;} (); 2. jquery notation The above is a small set to the introduction of JS to fill out the bank card number of every 4

Day4 regular expression, regular expression 4 digits Syntax: Regular Expressions are functions that process strings. We also have many such formulas in Excel functions. Because I have learned some Excel statements, let's take a look at the different methods. Import re # import re module to process the regular expression Module P = re. compile ("^ [0-9]") # generate the regular object to be matched. ^ indica

the penultimate start position. length If this parameter is set and is positive, the string length of the substring being replaced is indicated. If set to negative, it represents the number of characters at the end of the substring to be replaced string . If this parameter is not provided, it defaults to Strlen ( string ) (the length of the string). Of course, if it length is 0, then the function is where it will be replacement inserted string start .

/** * User Input phone number, judge whether reasonable or not? Ask, judge the length and judge the input is reasonable * Hide the user phone number in the middle of 4, * ideas: * *. With regular judgment conditions: Length 11-bit judgment there are two methods, regular {11} and Length () ==11. Input content with regular judgment * telephone number of the regular: "() [0-9][\\d]{8}| (15) [0-9] [\\d] {8} "*/ Public class StringDemo4 { publicstaticvo

The first: Whether the inverse number is equal to the original number#include The second type: the traditional way to find the number on a Chichong and then compare the bit and thousands, 10 and hundreds#include The third method uses the remainder formula to save the numbers on each digit first in the array a, then compare a[0] and a[3],a[1] and a[2]. Similar to the above, because it must be a four-digit number, so it is a[0] to a[3], this topic can refer to the previous notesC Programming: Dete

The numbers 1, 2, 3, and 4 can constitute three digits without repeated numbers. List For (INT I = 1; I { For (Int J = 1; j { If (I = J) { Continue; } For (int K = 1; k { If (I = k | j = K) { Continue; } Int num = 100 * I + 10 * j + K; Results. Add (Num ); }}}System. Out. println ("the

"Short A: 4" -- specifies the member variable of the number of digits The following code is sometimes used in struct or class. Struct s{Short A: 4;Short B: 6;Short C: 8;}; This is a property of struct and class. It specifies the number of digits of a variable while declaring the variable. The short type

How to make float keep two decimal places or decimal placeshttp://meryvn.blog.163.com/blog/static/36962664201173010402629/Two methods:Import java.math.*;......Method 1:float F = 34.232323;BigDecimal B = new BigDecimal (f);Float F1 = B.setscale (2, bigdecimal.round_half_up). Floatvalue ();B.setscale (2, bigdecimal.round_half_up) indicates rounding, reserving two decimal placesMethod 2:float scale = 34.236323;DecimalFormat fnum = new DecimalFormat ("# #0.00");String Dd=fnum.format (scale);SYSTEM.O

] Key3! = A[i]) {count1++; Key1 = A[i]; }Else if(Key1 = = A[i]) {count1++; }Else if(Key2!=a[i] key3!=a[i]) {count1--; }if(!count2 key3! = A[i] key1!=a[i]) {count2++; Key2 = A[i]; }Else if(Key2 = = A[i]) {count2++; }Else if(Key1!=a[i] key3!=a[i]) {count2--; }if(!count3 key1!=a[i] key2!=a[i]) {count3++; Key3 = A[i]; }Else if(Key3 = = A[i]) {count3++; }Else if(Key1!=a[i] key2!=a[i]) {count3--; }