String type representation
Can use single or double quotes (can only represent a single line)
Triple single quotes or triple double quotes to indicate multi-line data, triple single quotes can also be used as comments
Role: Redundancy of string representation can handle the case where quotes are in strings.
the index of the string
Forward 0 starts reverse -1 starts
string slice
<string>[M:N] from M to N-1
Where M and N can be missing, M missing means from the beginning, N missing is until the end
[M:N:K] Slice the string according to the step size K
Such as "012345678" [1:8:2] the result is "1357"
Application: <string>[::-1] means reverse order
Escapes\
\"Indicates that there is " in the string
The specific meaning of the escape character in combination with a specific character
\b fallback \n \rstring operator
| Operators and usage | describe |
| x + y | concatenate two strings |
| n*x or x*n | Copy the string n times |
| x in s | Returns True if x is a substring of s; otherwise returns False |
Input: an integer from 1-7, indicating the day of the week
Output: The week string corresponding to the input integer
For example: input 3, output Wednesday
Solution one:
#WeekNamePrint.py
weekStr = "Monday Tuesday Wednesday Thursday Friday Saturday Saturday"
weekId = eval(input("Please enter the week number (1-7): "))
pos = (weekId - 1) * 3
print(weekStr[pos:pos+3])
Solution two:
WeekStr = "One Two Three Four Five Six"
WeekId = eval(input("Please enter the week number (1-7):"))
print("Week" + WeekStr[WeekId-1])
String handling functions
| function and usage | describe |
| len(x) | length, returns the length of the string; For example, the result of len("one two three 123") is 6 |
| str(x) | the corresponding string form of any type x str(1.34) results in "1.34", str([1,2]) results in "[1,2]" |
| hex(x) or oct(x) | string of hexadecimal or octal lowercase form of integer x The result of hex(2) is "0x1a9" |
| chr(u) | x is Unicode encoding, return its corresponding character |
| word (x) | x is a character, return its corresponding Unicode code |
Unicode encoding
- Uniform character encoding, which is an encoding method that covers basically all characters
- From 0 to 1114111 (0x10ffff) space, each encoding corresponds to a character
- Every character in a Python string is a Unicode character
String handling methods
A method refers specifically to a function <b>() in the <a>.<b>() style
| method and use | describe |
| str.lower()或str.upper() | Returns a copy of the string, all uppercase or lowercase For example, ""AbCd".lower() results in "abcd" |
| str.spilt (sep = None) | Returns a list consisting of parts of str split according to sep "A,B,C".split(",") results in ['A','B','C'] |
| str.count(sub) | Returns the number of times the string appears in str "a apple a day".count("a")结果为4 |
| str.replace(old,new) | Returns a copy of the string str, with all old strings replaced with new "hel".replace("l","llo") results in "hello" |
| str.strip(chars) | Strip the characters listed in the left and right chars from str “=python =”.strip(" =p")结果为"python” |
| str.jojn(iter) | 在iter变量除最后元素外每个元素后增加一个str 如“,”.join("12345")结果为“1,2,3,4,5” |
| str.center(width,fillchar) | width代表宽度，fillchar代表填充字符 |
字符串类型的格式化
字符串格式化使用.format()方法用法如下
<模板字符串>.format(<逗号分隔的参数>)
print("", end="")如果有end=“”表示没有换行