String Formatting for Python Learning
- 2021-12-11 18:28:06
- OfStack
String stitching% s% (% s means 1 string type data str will be inserted)
It means that% s is a placeholder, and the% at the end of the sentence is the value to be filled in before
a = ' I am %s I 16 Twenty five years old ' %'adam'
print(a) # I am adam I 16 Twenty five years old
1. There are many such placeholders
1.% s (str) This is universal and can accept all kinds of data. When it writes floating-point numbers, it does not round up 4 and enter 5
2,% d (int) Insert integer digits
3.% f Floating Point Number Print Floating Point Number (Decimal)
It is best to use them differently, not just% s
2. Specific usage
1. You can insert several more values at a time
b = 'adam'
a = ' I am %s I %d Twenty five years old ' %(b,16)
print(a) # I am adam I 16 Twenty five years old
2. Print floating-point numbers (decimals)
Here, the first two places of f mean to reserve two decimal places
a = ' I %.2f Twenty five years old ' %16.53333 # Keep two decimal places Will proceed 4 Shed 5 Into
print(a) # I 16.53 Twenty five years old
3. Print percentage
Adding 2% after f means showing 1% after the inserted value
a = ' Content %.2f%%' %16.53333
print(a) # Content 16.53 %
4. Call the dictionary for splicing
It populates the placeholder value by indexing key
a = ' I am %(name)s I %(age)d Twenty five years old ' %{'name':'adam','age':16}
print(a) # I am adam I 16 Twenty five years old
5. sep sets the division symbol
The assignment of sep is a dividing symbol, which will be filled in the space inside the quotation marks between each element in turn
print('a','b','c','d',sep = ' = ' ) #a = b = c = d
6. flags Format Symbol
This is not very common
+, right alignment can set the total length of inserted characters, and the missing bits are not marked with spaces
a = ' I am %(name)+20s I %(age)d Twenty five years old ' %{'name':'adam','age':16}
print(a) # I am adam I 16 Twenty five years old Left alignment can be set to count the total length of the inserted characters, and the missing bits are not marked with spaces
a = ' I am %(name)-20s I %(age)d Twenty five years old ' %{'name':'adam','age':16}
print(a) # I am adam I 16 Twenty five years old Space, right-aligned
0, right-aligned
3. format
1. Splicing is used by default
format also fills elements inside strings through placeholders
Use {} curly braces for placeholders. By default, elements are filled in the preceding curly braces in turn
If the number of elements filled in is insufficient, an error will be reported
a = ' I am {} , I {} Twenty five years old '.format('adam',16)
print(a) # I am adam , I 16 Twenty five years old
2. Splice with indexes and slices
Use the index bits of elements to splice. You can take 1 element repeatedly but you can't exceed the index bits of Yuan Zu
a = ' I am {1} , I {0} Twenty five years old '.format('adam',16)
print(a) # I am 16 , I adam Twenty five years old Splicing by slices
b = 'adam'
a = ' I am %s I %d Twenty five years old ' %(b,16)
print(a) # I am adam I 16 Twenty five years old
3. Call Yuanzu for splicing
Placement in the form of variable name
b = 'adam'
a = ' I am %s I %d Twenty five years old ' %(b,16)
print(a) # I am adam I 16 Twenty five years old
4. Use a dictionary as the element library of format
Simply prefix the format element library with two asterisks
b = 'adam'
a = ' I am %s I %d Twenty five years old ' %(b,16)
print(a) # I am adam I 16 Twenty five years old
5. Use lists as an element library for format
Just prefix the format element library with * two asterisks
It can also be combined with index splicing
a = ' I am {2} , I {1} I like to eat. I'm 20 years old {0}'.format(*['adam',16,' Braised '])
print(a) # I am braised, and I 16 I like to eat. I'm 20 years old adam
6. Placeholder operator
You can also put caret symbols such as placeholders in the position of placeholders
These symbols perform the corresponding transformation calculation on the inserted assignment
{: b} binary
{: o} Octal
{: d} Integer type
{: x} Hexadecimal and partially lowercase letters
{: X} Hexadecimal and partially uppercase letters
{:%} Display percentages default to 6 decimal places
b = 'adam'
a = ' I am %s I %d Twenty five years old ' %(b,16)
print(a) # I am adam I 16 Twenty five years old PS:
What # * and * * mean is
1, * Take out the elements in the list once in order
2. * * is to take out the key values of the dictionary in turn and change them into the form of variable assignment: (a= 'adam', b = 16, c= 'Braised')
PS
The output background font format and font background color can be set by the following command
From\ 033 [43; All characters between 1m and\ 033 [0m are added with background color, 43 controls the color of font background filling, font format, etc.
b = 'adam'
a = ' I am %s I %d Twenty five years old ' %(b,16)
print(a) # I am adam I 16 Twenty five years old
Summarize
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