Summary of usage of str built in functions in python

  • 2021-08-31 08:31:01
  • OfStack

In the process of using python, we should often encounter str built-in functions when typing code. In order to prevent confusion, this paper summarizes str built-in functions. 1 String lookup classes: find, index; 2. String judgment classes: islower, isalpha;; 3. Content judgment classes: tartswith, endswith;; 4. Operation class functions: format, strip and join.

1. String lookup classes: find, index

find and index both look up whether a string contains a substring;

The difference between the two is that index will report an error if it can't find a string, while find will return-1;

rfind, lfind are left-start lookups or right-start lookups.

2. String judgment classes: islower, isalpha

The characteristic of this kind of function is the beginning of is

isalpha: To judge whether it is a letter, you should pay attention to two points:

The default premise of this function is that the string contains at least 1 character. If it does not, it returns false

Chinese characters are considered as alpha. This function cannot distinguish English letters from Chinese characters. Please use unicode code to distinguish Chinese and English

Function of isdigit, isnumeric and isdecimal

islower determines if it is lowercase

3. Content judgment class

startswith, endswith: Does it begin or end with XXX

4. Operate class functions

format: Formatting function

strip: Delete characters on either side of the string (default space). You can specify characters instead of deleting one, but qualifying consecutive characters from scratch.

rstrip, lstrip Delete the right/left character.

join: Splicing strings


s1='$'
s2='-'
s3=' '
ss=['Today','is','a','good','day']
print(s1.join(ss))
Today$is$a$good$day
print(s2.join(ss))
Today-is-a-good-day
print(s3.join(ss))
Today is a good day

Instance extension:


>>>s = 'RUNOOB'
>>> str(s)
'RUNOOB'
>>> dict = {'runoob': 'runoob.com', 'google': 'google.com'};
>>> str(dict)
"{'google': 'google.com', 'runoob': 'runoob.com'}"
>>>

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