Note five: Python string

A: Learning content

• String type
• String type judgment
• String Type Mutual transfer
• String Little Exercise

Two: String type

1. basestring

string - related data types in Python are: str and Unicode, both of which are basestring subclasses , str and Unicode are visible as two different types of string objects

2. Byte String type

bytestring= ' Hello world! '

You can see the type of this bytestring is str

3. Unicode string type (plus u in front of normal string)

Unicodestring=u ' Hello Unicode world! '

You can see that the type of this unicodestring is Unicode

Three: String type judgment

1. Determine if it is a string (including STR and Unicode)

#encoding =utf-8

s = "Hello normal string"

u = U ' Hello Unicode '

If Isinstance (s,basestring):

Print U ' is a string '

If Isinstance (u,basestring):

Print U ' is a string '

The result is: either the str string or the Unicode string belongs to the subclass of the basestring class

2. Determine if it is Unicode

#encoding =utf-8

s = "Hello normal string"

u = U ' Hello Unicode '

If Isinstance (S,unicode):

Print S,u ' is Unicode '

If Isinstance (U,unicode):

Print U,u ' is Unicode '

The result of the operation is:

3. Determine if STR is

#encoding =utf-8

s = "Hello normal string"

u = U ' Hello Unicode '

If Isinstance (S,STR):

Print S,u ' is str '

If Isinstance (U,STR):

Print U,u ' is str '

The result of the operation is:

Four: String type mutual transfer

1. Do not specify encoding decoding type for mutual transfer - Use system default encoding

#encoding =utf-8

s= "byte string"

Print type (s)

#str Turn Unicode

U = S.decode ()

Print type (u)

#uncode Turn str

backtobytes = U.encode ()

Print type (backtobytes)

You can see that both Unicode and decode do not specify a name for the codec, and the system's default encoding is used.

2. Specify the encoding decoding type for mutual transfer

#encoding =utf-8

s = "Hello normal string"

Print U "byte string", type (s)

#str Turn Unicode

U = S. Decode ("UTF-8")

Print U "Unicode string", type (U)

#uncode Turn str

backtobytes = U.encode ("UTF-8")

Print U "byte string", type (backtobytes)

The result of the operation is:

Five: String small exercise

1. Small exercise : A string of odd coordinates in the output character string

A = ' gloryroad '

". Join ([a[x] for x in Xrange (Len (a)) if x%2==1])

2. Little exercise Two: Write the string to lowercase, lowercase to uppercase output

s= ' ADBABC '

S.swapcase ()

3. Little exercise Three: ABCDEFGCCC the string into the order of the first C to F and then output the entire string

s1= ' ABCDEFGCCC '

S2= "

Flag=true

For I in S1:

If i== ' C ' and flag:

s2+= ' F '

Flag=false

Else

S2+=i

Print S2

The result of the operation is:

4. Small exercise four: output of 3 of the number such as :34,153 , etc.

print [x for x in range (1001) if ' 3 ' in str (x)]

The above practice may not all of you beginners can understand, do not worry, follow-up python Learning notes we will learn every detail one by one .

Note five: Python string