Author: vamei Source: http://www.cnblogs.com/vamei welcome reprint, please also keep this statement.
The Python built-in (built-in) function is created with the running of the python interpreter. In pythonProgramYou can call these functions at any time without defining them. The most common built-in functions are:
Print ("Hello world! ")
In the python tu
more than 160ms multiple times and can be seen as less efficient than Python 2
Wall time:176 ms
Wall time:183 ms
Run the test function multiple times with the%timeit test
def for_test (container):
for I, Num in enumerate (container):
num = num/5*10 + 12-8
container[i] = num
Co Ntainer = List (range (1000000))
%timeit for_test (Container)Python
: Jump out of the current entire loop1Flag =False2 forIinchRange (10):3 ifI :4 Continue #0 to 5 is skipped, the print statement behind it cannot be executed5 Print(i)#When i = 6, start printing6 forJinchRange (10):7 Print(j)8 ifj = = 5:9Flag =TrueTen Break #interrupts the current loop, and the second for loop is interrupted One #If flag: A #break
Python for loop clever use (iteration, list generation), python generationIntroductionWe can use the for loop to iterate the list, tuple, dict, set, and string. dict is not sequential in storage, so iteration (traversal) the order
List and looping issues
Write a function tag_count whose parameters are listed as a list of strings. The function should return the number of XML tags in the string. XML is a data language similar to HTML. You can determine whether a string is an XML tag, starting with the left angle bracket "
You can assume that the list of strings as input does no
quotation marks for multi-line strings, or multiline commentsJob 1Jump out of the multilayer loop, three-layer cycle, the innermost layer, jumping out of 3 layers,Job 2Shopping Cart Program (knowledge points, loops, lists,)python shopping.pyInput your salary:5000you can buy the following things:1.iphone 58002.coffee3.book4.condom>>: 1can't afford to print, how much is the difference?>>:2can afford to put i
Python's for Loop and C, C + + languages such as the structure of the For loop is still very different, but it is very easy to get started, the Python list is similar to the C language of the array, but compared to the function of the array is more powerful, the joke is said to hit the array of hormones.
For
Python: Basic Introduction 3 --- (for loop + list) the structure of the for loop in Python is quite different from that in C, C ++, and other languages, however, it is easy to get started. The Python
the current cursor position in the file ##文件的光标的移动# obj.seek (0) #光标回到文件最开始处, the second argument can not be written, the default is the start of a file 0# Obj.seek (0,0) #光标回到文件最开始处Obj.seek (12,0) #光标回到以文件0开始, 12th characterPrint Obj.tell ()Obj.seek (6,1) #光标从当前位置1开始, 6th characterPrint Obj.tell ()Obj.seek (3,2) #光标从文件最后2开始, 3rd characterPrint Obj.tell () #0 displays the current position of the cursor, which is the No. 0 character# Seek Summary# second argument, 0 for file start, 1 for file cu
In Python's list loop traversal, the correct method for deleting data is pythonlist.
When I was a beginner in Python, I encountered such a problem. When traversing the list, I deleted the Qualified Data, but always reported an exception. The Code is as follows:
num_list = [1, 2, 3, 4, 5]print(num_list)for i in range(le
This article mainly introduces the usage of list loop statements in python, and describes in detail the list parsing of Python in the form of examples, including various common traversal operations and principle analysis, for more information about the
comparison is 0 2 *, 22, 13, 99, 11] The value of the list under this comparison is 0 3 [6, 22, 13, 99, 11] The value of the list under this comparison is 0 4 [6, 22, 13, 99, 11] [6, 22, 13, 99, 11] ++ this internal cycle ends with ++ this comparison list under the standard value of 1 2 ********* internal, 13, 22, 99, 11] values under the
This example describes the use of the list loop statement in Python. Share to everyone for your reference. The specific usage analysis is as follows:
One of the powerful features of Python is its parsing of the list, which provides a compact way to map a
Next we will do some interesting things. if you follow the progress, you will find that you can use the if statement and Boolean expression to do a lot of things.
In any case, the program will do some repetitive tasks. Next we will print a list variable with a for loop. During this exercise, you must understand their meanings and functions.
Before using the for loop
Loop structure is a common structure for programming. The loop is especially required when processing serialized objects (such as list, dict, and tuple. However, in Python, there is a more convenient way of processing, that is, list derivation and function programming.
If we
bounce loop, continue is the end of the current loop into the next loop.7, List (array)stus=[' Saki ', ' Yuri ', ' MIMO ' #定义数组Subscript (angle, index, number) 0 1 2Stus[0] means Saki stus[1] represents Yuri, subscript starting from 08, list additions and deletions to check
efficiency of the list deduction is actually the same as for the for.def Add (x): return for inch Array] # loops, Best of 3:180 us per loopAs always: simple cyclic mapping operations, we recommend the form of a list deduction, which is more efficient and faster. Complex cyclic mapping operations, we recommend using a For loop, which makes the code easier to
This example describes the use of the list loop statement in Python. Share to everyone for your reference. The specific usage analysis is as follows:
One of the great features of Python is its parsing of lists, which provides a compact way to map a list to another
print generator itself will display generator instead of listL = [i forIinchRange (1,11,2)]#outside is [] is a list#Space change time, memory consumption is large, but no longer CPU#list It is to put all the elements in the memory, here will apply for 5 memory spacePrint(l)#[1, 3, 5, 7, 9]L1 = (i forIinchRange (1,11,2))#outside is () the word is generator#The Generator generator saves memory than the
number of digits of integers and decimals:>>> '%2d-%02d '% (3, 1)' 3-01 '>>> '%.2f '% 3.1415926' 3.14 '%s always works, it converts any data type to a string:>>> ' Age:%s. Gender:%s '% (True)' Age:25. Gender:true 'For Unicode strings, the usage is exactly the same, but it is best to ensure that the substituted string is also a Unicode string:>>> u ' Hi,%s '% u ' Michael 'U ' Hi, Michael 'The% inside the string is an ordinary character that needs to be escaped and is represented by a percentA da
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