Orderly arrangement

introduction

In the process of learning mathematics , We sometimes encounter the problem of permutation and combination . Several elements are given in the title , Find out how many different combinations these elements can have . And now we use python Medium for A loop can produce results quickly , And output these combinations one by one .

problem

Yes 1,2,3,4 Four numbers find out how many different and non repeating three digits can be generated by four numbers ( It cannot contain 122,133 similar ), Output these three digits at the same time .

Method

First, take these numbers as a string , Reuse for Loop through the string , Three digit numbers are required to be nested three levels for loop （ Note that the indentation ）, Reuse if Statement to determine whether a number is repeated . Finally, set a variable as a counter , Count the total number of combinations .

Experimental results and discussion

Through the experiment 、 Practice has proved that the proposed method is effective , Is able to solve the problem raised at the beginning .

Code list 1

m='1234' n=0 for i in m: for j in m: for q in m: if (i!=j) and (j!=q) and (q!=i):                n += 1 print(i,j,q) print(' Yes ',n,' individual ')

Conclusion

For this orderly arrangement problem , Put forward for Loop nested method , Through the experiment , The method is proved to be effective . Because there are three nested loops , The running speed will decrease . And once there are too many elements to be combined , Need to nest more loops . In the future, we can explore other ways to solve this kind of permutation problem .