Python built-in function usage

1.Python raw_input () function

Function: Raw_input () is used to get input from the console, treat all inputs as strings, and return string types.

Attention:

Both the input () and raw_input () functions can receive strings, but raw_input () directly reads the console input (any type of input it can receive). For input (), it wants to be able to read a valid Python expression, that is, you must enclose it in quotation marks when you enter a string, or it will throw a syntaxerror.

Unless there is a special need for input (), it is generally recommended to use raw_input () to interact with the user.

The Python3 input () is the STR type that is received by default.

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2.Python Range () function

Grammar:

Range (Start,stop[,step])

Parameter description:

• Start: Count starts from start. The default is starting from 0. For example, range (5) is equivalent to range (0, 5);
• Stop: Count to stop ending, but not including stop. For example: Range (0, 5) is [0, 1, 2, 3, 4] No 5
• Step: Step, Default is 1. Example: Range (0, 5) is equivalent to range (0, 5, 1)

Example:

>>> Range (1, 2, 3, 4, 5, 6, 7, 8, 9]>>> range (1,11) [1, 2, 3, 4, 5, 6, 7, 8, 9]>>> Range (0,20,5)   # step is 5[0, 5, ten]>>> Range ( 0,14,33, 6, 9, >>>Range (0,-10,-2)    # negative numbers [0,-2, -4,-6,-8  ]>>> Range (0) []>>> Range (1, 0) []>>> Range (5,1) []

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The following is the use of range in for, looping out each letter of dictionary

>>> x='dictionary' for in range     (len (x)): ... Print (X[i]) ... dictionary

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Practice Example 1:

title: There are four numbers: 1, 2, 3, 4, how many different and no repetition of the number of three digits? What's the number?

Program Analysis: can be filled in hundreds, 10 digits, single digit numbers are 1, 2, 3, 4. Make all the permutations and then remove the permutations that do not meet the criteria.

#!/usr/bin/env python#-*-coding:utf-8-*-#Example 1 forIinchRange (1,5):     forJinchRange (1,5):         forKinchRange (1,5):            if(I!=J) and(i!=k) and(j!=k):Printi,j,k#Output:1 2 31 2 41 3 21 3 41 4 21 4 32 1 32 1 42 3 12 3 42 4 12 4 33 1 23 1 43 2 13 2 43 4 13 4 24 1 24 1 34 2 14 2 34 3 14 3 2

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Pop () method in 3.List: the pop () function removes an element from the list (the last element by default) and returns the value of the element.

#!/usr/bin/env python#-*-coding:utf-8-*-List=['ABC','Jack','Taobao']LIST_POP1=list.pop (0) List_pop2=list.pop (1)Print "The first time you delete the item is:", List_pop1Print "The items that are deleted the second time are:", LIST_POP2#Note: After the first deletion, the remaining list elements in List.pop (1) are ' Taobao ', not ' Jack 'Print "the columns are shown in the following:", List

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The uniform () function and the Randint () function in the 4.Python random module

The uniform () method randomly generates a real number in the [x, Y] range, that is, excluding Y, syntax:

Import Random

Random.uniform (x, y)

The Randint () function randomly generates an integer N within a range, in the range of [A, b], a<=n<=b.

Grammar:

Import Random

Random.randint (0,9)

　　

Python built-in function usage