Python Basic Learning Note one

First, quotation marks and comments:

1. In Python, single quotation marks ("") and double quotation marks ("") are not distinguished, and both single and double quotation marks can be used to identify a string.

      Print ("Hello")      rint (' Hello ')

2, single quotes and what u that quotation marks can be nested with each other, but not cross-use.

3, #表示单条注释; Multiple lines of comments are expressed in quotation marks.

Second, the circulation

1, if loop, python through the IF statement to achieve branch judgment, Syntax: If......else ...

A=0b=1if a>b:    print (' A relatively large ') Else:    print (' B larger ')

Note: Python uses indentation to determine the body of the statement;

The IF statement uses the = = operator to determine equality, and by the! = operator to indicate that you do not want to wait;

The IF statement can be judged by a Boolean type:

A=trueif A:    print (' A  is  true ') Else:    print (' A was not true ') output  A is true

If statement multiple conditional judgment:

If  score >=90:    print (' excellent ') Elif  score >=75:    print (' good ') elif  score >=60:    print (' Pass ') Else:    print (' fail ')

　　

2. For loop

For I in  Range:    print (i)

Note: The range (Start,end[,step]) range () function loops from zero by default, start indicates the start position, end indicates the ending position, step identifies the step of each cycle

3. While loop

While count<10:     print (' hello,world! ')     Count=count+1else:     print (' Bye. ‘)

　　

Break, exit the loop, break can only be used inside the loop

While count<10:     print (' hello,world! ')     count=count+1     if count==5:        break   

　

The use of continue, the role of continue is to exit this cycle

While count<10:     print (' hello,world! ')     count=count+1     if count==5:        continue     

　　

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Python Basic Learning Note one