1. String operations
① repeatedly output string
print("hello" * 2)
② slicing operation, the same list
print("hello" [1:])
③in determines whether elements in strings, the list is the same
print("e" in "hello")
④ formatted output
name = "kathrine"
print("%s is a good boy" % name)
⑤ string concatenation is not recommended.
2. String built-in method
①join method, string concatenation, before join a string or an empty string, the content of the list or add a tuple format.
d = "000".join(["a","b"])
②.count method, the number of an element in the string.
print("hello".count("l"))
③.capitalize string capitalized
print("hello".capitalize())
④..center (total number of characters, "other content except the content center"), center
print("hello".center(50,"-"))
⑤.startswith, in order to determine whether an element is a start, can be a range, it returns a Boolean value.
print("hello".startswith("he"))
⑥ added \ T (tab character) in the string, it can be used to set the number of spaces .expandtabs tabs.
print("he\tllo".expandtabs(5))
⑦.find lookup index value of a certain element in the string, and return the index value, as this element does not exist, returns -1.
print("hello".find("h"))
Another way ⑧.format / .format_map formatted output
format method
The formatting output with the parameters of the position in the format process.
name = "my name is {0},my age is {1}-{0}"
val = name.format ("kathrine",20)
print(val)
If the parameters in parentheses format is a list, to add *
name = "my name is {0},my age is {1}-{0}"
val = name.format ( * ["kathrine",20])
print(val)
The format parameter can be a method of direct variable assignment
nAme = input(">>:")
info = "my name is {name},age is {age}"
val = info.format(name = nAme , age =18 )
print(val)
The format argument is a case of dictionaries, with two **
name = "My name is {name}, the age {age}"
dic = {'name':'kathrine','age':18}
val = name.format(**dic)
print(val)
format_map method parameter must be a dictionary
info = "my name is {name},age is {age}"
dic = {"name":"kathrine","age":19}
info.format_map val = (say)
print(val)
Note: The dictionary will be reflected in a subsequent essay.
⑨index string index value of a certain element, as this element is not included, it is given
print("hello".index("h"))
⑩isalnum determine whether the string contains letters or numbers, if they contain spaces or special characters will return an error value
print("hello12345".isalnum())
11.isdecimal determine whether a decimal
print("hello123".isdecimal())
12 detects whether a string consisting only of letters
print("h123".isalpha())
13 determines whether the string is an integer number
print("123.111".isdigit())
print("123.11".isnumeric())
14 variables to determine whether it is illegal
print("123ggg'.isdentifier())
15 checks whether all lowercase letters
print("123ggg'.islower())
16 check whether all uppercase letters
print("123ggg'.isupper())
17 is a blank check whether
print( " ".isspace())
18 to determine whether the title, the title is characteristic of each word capitalized
print("Abc Def".is title())
print("abc Def".is title())
19 string in all uppercase to lower case
print("abcQW12".lower())
20 all lowercase string becomes uppercase
print("abcQW12"。upper())
21 and the center is similar, but the string on the left
print("hello".ljust(50,"*"))
22 and the center is similar, but the string on the right
print("hello".rjust(50,"*"))
23 before and after removing the string line breaks and tabs spaces
.strip strings before and after the newline and tab and remove the spaces (\ n newline)
.lstrip the left of the string line breaks and tabs is removed and spaces (\ n newline)
.rstrip the right of the string newline and tab and remove the spaces (\ n newline)
print(" abc Def ".strip())
print(" abc Def\n ".strip())
Alternatively content 24, .replace ( "content to be replaced," "desired content", replace several values)
print("hello".replace("h","f",1))
25 real index position
print("hello".rfind("e"))
26 split into a string list to an element in the string of target partition, the partition object will not be output
print ( "ab cdef" .split ( "")) from the space Split
print ( "ab cdef" .split ( "b")) from the split b
27 from right to left split rsplit ( "Where minute", several times)
print("abc bws webs".rsplit("b",1))
28 string becomes the title format
print('abc bef.title()')