Operator for string loop

1. Operators

1.1 Assignment Operators

• = += -= *= /= //= %= **=

1.2 Comparison Operators

• < > = <= == !=

1.3 member operator

• in not in

1.4 Logical Operators

• and or not
  • and two are true and taking the foregoing, and the latter two are taken false
  • or both are taken back or the true, false take both of the front or

0 and 9 and 8 and 5 #0，有一假取假
4 or 0 or 9 or 8    #4，有一真取真

Arithmetic operators 1.5

• + - / // ** %

2. while else

• while loop the loop condition is satisfied to go, go else condition is not satisfied
• while walking cycling conditions established body of the loop when it comes to break this cycle is over do not go else

3. Integer

• python2 in long long integer python3 not, all of type int

4. Boolean value

• Boolean value is non-zero digit of the time is False True 0

print(bool(0))      #False    
print(bool(-9))     #True

• Boolean value to a string when the space is not True, space is False

print(bool("你好"))     #True
print(bool(" "))         #False

print(int(True))     #1
print(bool(False))   #0

print(str(True))       #字符串类型的True
print(str(False))      #字符串类型的False

The subscript string

5.1 subscript

• From left to right number 0 - n
• To the right operand -1 --- - The length of the string
• If the index to find out of bounds, on the error

a="你好你好"
print(a[2])       #你
print(a[-3])      #好

5.2 slices, step

• msg [3: 5] is not taken before and after taking

msg = "今天是个好日子！"
print(msg[3:5])  #个好

• msg [-5: -2: 1] -25 -2 end position of a starting position of the step 1 is not written default
• 1 represents -1 for left to right from right to left

msg="今天是个好日子！"
print(msg[-5:-2])  #个好日

msg = "今天是个好日子！下雨了！"
print(msg[2:6:2]) #是好

msg="今天是个好日子！下雨了！"
print(msg[6:1:-1])  #子日好个是

• If a slice out of bounds, get to the last content

6. The method of string

6.1 s.capitalize()

• Capitalized

s = "zhyyz"
s1=s.capitalize()
print(s1)        #Zhyyz

6.2 s.upper()

• ALL CAPS

s = "zhyyz"
s1=s.upper()
print(s1)         #ZHYYZ

6.3 s.lower()

• All lowercase

s = "ZhYYz"
s1=s.lower()
print(s1)          #zhyyz

6.4 s.count("Y")

• Returns the number of

6.5 s.endswith("z")

• To what end

6.6 s.startswith("y")

• To what end

6.7 s.find("Y")

• By element lookup to find no subscript -1

6.8 s.index("p")

• Find index by elements that do not look on error

s = "zhyyz"
print(s.count("y"))      #2
print(s.endswith("z"))   #True
print(s.startswith("y")) #False
print(s.find("y"))        #2

6.9 format() ****

• String formatting

  s= "zhy"
  s1="zhy{0},{2},{1}"
  s2="zhy{a},{b},{c}"
  print(s.format("你好","yz","少年"))  #zhy
  print(s1.format("你好","yz","少年"))  #zhy你好,少年,yz
  print(s2.format(a="你好",b="yz",c="少年")) #zhy你好,yz,少年

6.10 s.join() ***

• Insert Character

s= "zhyyzily"
#print(s.join("_"))  #错误
print("_".join(s))   #z_h_y_y_z_i_l_y

6.11 s.split() ****

• Split

s = "zhyyzilzy"
print(s.print("z"))  #['', 'hyy', 'il', 'y']

6.12 s.strip() ****

• Spaces on both sides of the end turn Tuotuo newline \ n

s = "       zhyyzily           "
print(s.strip())           #zhyyzily

• Take off the specified character if there are spaces off spaces

s = "  zhyyzily  "
print(s.strip(" y"))  #zhyyzil

6.13 s.replace ****

• Replace the first release to be replaced and the second is to replace the contents of

s = "  zhyyzily  "
print(s.replace("z","y"))  #  yhyyyily  

6.14 s.swapcase()

• Case conversion uppercase converted to lowercase lowercase to uppercase

6.15 s.title()

• Special sign division of each word capitalized

s = "  zhy yz il y  "
print(s.title())  #  Zhy Yz Il Y  

6.16 s.isdigit ()

• Judgment is not a pure digital

6.17 s.isalpha()

• Disc on is not Chinese characters and letters

s = "你好啊zhy撒大声地"
print(s.isalpha())  #True

7. for loop

s="你好嗨啊"               #你
s_len= len(s)            #好
count=0                 #嗨
while count < s_len:     #啊
    print(s[count])
    count += 1

• for keywords in the keyword variable i object to iterate colon:

  for loop structure

s="你好嗨啊"
for n in s:
    print(n)