Basic Python Tutorial Chapter 5th-Conditional loops and other statements

1. A statement block is a set of statements that executes or executes multiple times (a loop statement) when the condition is true (a conditional statement). Put a space in front of the code to indent the statement to wear a statement block. Each row in the block should be indented in the same amount. In Phyton, a colon (:) is used to identify the beginning of a statement block, and each statement in the block is indented (the same amount of indentation). When you fall back to the same amount of indentation as you have closed, it means that the current block is closed.

2, Boolean: false None 0 "" () [] {} that is, the standard value False and None, all types of number 0 (including floating-point long integers and other types) empty sequences (such as empty strings, tuples, lists) and empty dictionaries are false, everything else is interpreted as true, Includes the special value TRUE.

3. If related

Name=raw_input ("What's your name?")

If Name.endswith (' Gumby '):

print ' Hello.Mr.Gumby '

Else

print ' Hello. Stranger '

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Num=input (' Enter a number: ")

If num>0:

print ' The number is positive '

Elif num <0:

print ' The number is negative '

Else

print ' The number is zero '

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The = = Budget character Determines whether 2 objects are equal, and is to determine whether the two are equivalent (the same object)

An Assert statement is available if you need to make sure that a condition in the program must be true for the program to function

4. Circulation

While loop

While x<10:

Print X

X=x+1

For loop

words=[' This ', ' was ', ' an ', ' ex ', ' Parrot ']

For word in words:

Print Word

Range function Range (0,5) =[0,1,2,3,4]

The zip function compresses 2 sequences together, and then returns a list of 1 tuples

Statement that jumps out of the loop

Break jumps out of the loop, ends the loop, continue the current iteration, jumps to the next cycle.

While True:/break loop

6. List derivation use other lists to create a new list

[(x, Y) for x in range (3) for Y in range (3)]

7, pass the shrimp do not execute, Python can not have empty code block, so you may add pass

Del Delete objects that are not in practical

8 exec can dynamically create a code string

Eval Evaluation Expression

Basic Python Tutorial 5th-conditional loops and other statements