2018-5-27-python Full Stack development day11-string

Summary of String methods

1. Methods that must be mastered

1.1 Join ()

Stitching elements in a string according to a specific delimiter

　　

test=' who are you? 'print(test) v='* *'. Jion ( Test)print(v)

who are you, who are you * * * * * *

The format is special, first of all the characters need to be inserted into the front, in addition to not only the string, but also the dictionary, list, and so on into the string. Put the string behind Jion

1.2split (", 2)

Split the string, the first argument is what the benchmark, the second parameter is split several times, but after the split, the first parameter disappears

　　

test='alexalexalex'v=test.split ('l', 2) Print (v)

Output Result:

['a''exa'exalex' ]

Split with L as parameter, and divide two times, the output result does not retain L

1.3 Find to find a string

Find (' l ', 5,100)

Search for the string to find the first position in the interval.

　　

test='alexalexalexalex'v=test.find ('l', 2,10  )Print(v)

1.4 Strip

1.4.1 Strip can remove spaces on both sides of a string

　　

test='    Alex    'v=test.strip (test)print (v)
------
Alex

1.4.2 Strip can remove certain characters

　　　　

test='Alex'v=test.strip ('A')Print (v)

Output: Lex

1.5 Upper ()

Convert lowercase letters to uppercase

　　

test='Alex'v=test.upper ()print(v)

Output: ALEX

1.6 Lower ()

Convert uppercase letters to lowercase

　　

test='ALEX'v=test.lower ()print(v)

Output: Alex

2. Special usage

2.1 Gets a value from a string according to the index

　　

test='Alex'v=test[0]print(v)--------  A

2.2 Gets a value of a string based on the range

　　

test='Alex'v=test[0:3]print(v)------Ale 

The value that you want to get is determined by the range, which is the left-closed right opening interval, separated by a colon.

2.3len ()

Get string or other type of length

　　

test='Alex'v=len (test)print(v)-----4

Where, for example, the length of a list is calculated as a comma

2.4 For Loop to traverse

　　

test='Alex' for in test:    print(i)---- -----Alex .

Output strings or other types of values over time.

2.5 Replace

To replace a specific value in a string

　　

test='Alex'v=test.replace ('a','  BBBBBBBBBBB')print(v)----------Bbbbbbbbbbblex

In addition, you can limit the number of replacements

　　

test='alexa' v1=test.replace ('a','  BBBBBBBBBBB', 1) v2=test.replace ('a','  BBBBBBBBBBB', 2)print(v1,v2)--------------------  Bbbbbbbbbbblexa bbbbbbbbbbblexbbbbbbbbbbb

2.6 Range ()

Range can create consecutive numbers, or you can create discontinuous numbers.

Range (0,100)

>>> Create 0-99 of these sequential numbers, left closed right open interval,

Range (0,100,5)

>>> Create a number that starts at 0 and each 5 is a step

2018-5-27-python Full Stack development day11-string