Python basic syntax

First, line and indent

The biggest difference between Python and other languages is that Python's code block does not apply braces {} to control classes, numbers, and other logical judgments. Python's most distinctive feature is the use of indentation to write modules .

The amount of white space to indent is variable, but all code block languages must contain the same amount of indentation whitespace, which is strictly enforced.

As shown below:

If True:print "True" Else:print "false"

The following code will execute the error:

#!/usr/bin/python#-*-coding:utf-8-*-# if True:print "Answer" print "True" Else:print "Answer" # no strict indentation, Error print "False" on execution

after executing the code, the following error occurs:

$ python test.py File "test.py", line 5 if True: ^indentationerror:unexpected indent

Second, print output

#！ /usr/bin/python#-*-coding:utf-8-*-x= "A" y= "B" Print (x) print (y)

Third, if statement

Four, the dictionary
A dictionary is another mutable container model and can store any type of object.

Each key value of the dictionary (Key=>value) is split with a colon (:), each pair is separated by a comma (,), and the entire dictionary is included in parentheses ({}).

The format is as follows:

D = {key1:value1, key2:value2}

The key must be unique, but the value does not have to be.

The value can take any data type, but the key must be non-becoming, such as a string, a number, or a tuple.

A simple Dictionary instance:

Dict = {' Luwenjuan ': ' 123 ', ' Ningji ': ' 18 '}

You can also read the following dictionary:

Dict1 = {' abc ': 4456};

Dict2 = {' abc ': 123,456,45:12};

#!/usr/bin/python dict = {' Name ': ' Zara ', ' age ': 7, ' Class ': ' First '}; Print "dict[' Alice ']:", dict[' Alice ');

The result of the above example output:

dict[' Alice ']: traceback  (most recent call last):  file  "test.py",  line 5, in <module>    print  "dict[' Alice ']: ",  dict[' Alice ']; keyerror:  ' Alice ' 

Five, modify the dictionary to add new content to the dictionary method is to add new key/value pairs, modify or delete the existing key/value pairs of the following instance: #!/usr/bin/python dict = {' name ': ' Luwenjuan ', ' age ': ' Class ': ' Firs   T '};   dict [' age '] = 19;   doct [' School '] = "DPS School";   print "dict [' Age ']:", dict [' age '];  print "dict [' School ']:", dict [' School ']; Above example output: dict[' age ']: dict[' School ': DPS School

This article is from the "HCWJ" blog, make sure to keep this source http://luwenjuan.blog.51cto.com/10967115/1922431

Python basic syntax