1.str
The index of the string.
The index is the subscript, starting from the first 0 in the string, and so on.
a = 'ABCDEFGHIJK' print(a[0]) print(a[3]) print(a[5]) print(a[7])
Slicing is to intercept a string by index to form a new string. (Principle of the head regardless of the tail)
a = 'ABCDEFGHIJK' print(a[0:3]) print(a[2:5])
print(a[ 0 :]) #default to the end print(a[ 0 :- 1 ]) #- 1 is the last print(a[ 0 : 5 : 2 ]) #Add step size print(a[ 5 : 0 :- 2 ]) #reverse step size
String common methods
# *** upper: all uppercase
# lower: all lowercase
s = "laoNANhai"
s3 = s.upper()
s31 = s.lower()
print(s3)
print(s31)
#* 居中 center
s = "laoNANhai"
s2 = s.center(27,"*")
print(s2)
# *** startswith : Determine what content starts with,
# Return bool, which can be sliced, and slices are separated by commas.
# ***endswith
s = 'laoNANhai'
s4 = s.startswith('l')
s41 = s.startswith('lao')
s42 = s.startswith('N', 3, 6)
print(s42)
print( s4)
print(s41)
#***Find the index by element
# index: find the index by element, can be sliced, can not find an error
# find: find the index by element, can be sliced, can't find return -1
s = "Alex wusir aAQjinxing"
s7 = s .find('a')
print(s7)
s71 = s.find('A',2,)
print(s71)
s72 = s.index('Q')
print(s72)
#*** strip Remove leading and trailing spaces, newlines, and tabs.
ss = 'ablabsexsba'
s8 = ss.strip()
print(s8)
s9 = ss.strip('a')
print(s9)
s9 = ss.strip('abs')
print(s9)
# ***split str ---> list #The
default is to split by spaces,
s = 'wusir alex taibai'
st = 'wusir,alex,taibai'
st1 = 'QwusirQalexQtaibai'
s10 = s.split()
print(s10)
s101 = st.split()
print(s10)
s102 = st1.split('Q',2) #Let the split several times
print(s102)
#***join
# in some cases, list --- >str
s = 'alex'
s11 = '+'.join(s)
print(s11)
l = ['wusir', 'alex', 'taibai ']
s111 = ''.join(l)
print(s111,type(s111))
# repalce replace
s = 'small pink tender little pink tender ghlasdfg small pink tender'
# # s12 = s.replace('small pink tender', 'big hammer')
s12 = s.replace('small pink tender', ' sledgehammer',2) #replace how many
print(s12)
len() calculates the length
count() calculates how many times an element appears
#format formatted output,
1,
msg = 'My name is {}, this year {}, hobby {}'.format('Taibai', '20', 'girl')
print(msg)
2.
msg = 'My name is {0}, this year is {1}, my hobby is {2}, my name is still {0}'.format('Taibai', '20', 'girl')
print(msg)
3.
msg = 'My name is {name}, this year is {age}, and my hobby is {hobby}'.\
format(name='Taibai', hobby='girl', age='20')
print(msg)
isdigit() determines whether the string is a number
isalpha() determines whether the string is in English
isalnum() determines whether the string is composed of numbers and English