Read "stupid methodology python3", summed up the knowledge
Problem 1: Installation environment using the print function + practice main difference between double and single quotation marks to distinguish
Problem 2: comment symbol #
Problem 3: The operator precedence, with C / C ++, Java similar
The following operator precedence: down incrementally from this, the same behavior the same priority
Lambda # operator has the lowest priority logical operators: or logical operators: and logical operators: not members of the test: in, not in identity test : is, is not the comparison: <, <=,>,> =, =, ==! bitwise oR: | bitwise XOR: ^ bitwise aND: & shift: <<, >> addition and subtraction: +, - multiplication, division and modulo: *, /,% sign: + x, -x
Problem 4: variable name + print describes this form of print
print("There are", cars, "cars available.")
Problem 5: More printing method such as f "XXX"
my_name = 'Zed A. Shaw'
print(f"Let's talk about {my_name}")
Problem 6: continue to use the f "XX" Print
Problem 7: format printing method, may be employed end = '' instead of line feed
print("Its fleece was white as {}.".format('show'))
print(end1 + end2 + end3 + end4 + end5 + end6, end=' ')
print(end7 + end8 +end9 + end10 +end11 + end12)
显示如下：
Its fleece was white as show.
Cheese Burger
Problem 8: More print mode (print this way to see less)
formatter = '{} {} {} {}'
print(formatter.format(1, 2, 3, 4))
print(formatter.format("one", "two", "three", "four"))
print(formatter.format(True, False, False, True))
print(formatter.format(formatter, formatter, formatter, formatter))
# print("\n")
print(formatter.format(
"Try your",
"Own text here",
"Maybe a poem",
"Or a song about fear"
))
显示如下：
1 2 3 4
one two three four
True False False True
{} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {}
Try your Own text here Maybe a poem Or a song about fear
Problem 9: multi-line printing, a new line
Summary: Print mode
1）print("There are", cars, "cars available.") # 变量名直接打印
2）print(f"Let's talk about {my_name}") # 带有f"{}"的打印方式
3） 变量名+format()
hilarious = False
joke_evaluation = "Isn't that joke so funny?! {}"
print(joke_evaluation.format(hilarious))
4）print("Its fleece was white as {}.".format('show')) #
5）formatter = '{} {} {} {}'
print(formatter.format(1, 2, 3, 4))
print(formatter.format("one", "two", "three", "four"))
6）print('''
There's something going on here.
With the three double-quotes.
We'll be able to type as much as we like.
Even 4 lines if we want,or 5,or 6
'''） # 多行打印
Exercise 10: The escape character
11 Problem: The input () function, and a printing mode using the exercises described 5
print("How old are you?", end=' ')
age = input()
print("How tall are you?", end=' ')
height = input()
print("How much do you weight?", end=' ')
weight = input()
print(f"So,you're {age} old,{height} tall and {weight} heavy.")
12 Problem: The input () function prompt plus
age = input("How old are you?")
print ( "How old are you? {}". format (input ())) # prompt before running back to run in front of
Exercise 13: parameters, variables and unpacking
from SYS Import argv
# the Read at The WYSS Section for How to RUN the this
Script, First, SECOND,, THIRD, = argv
Print ( "at The Script IS Called:", Script)
Print ( "Your First variable IS:", First)
Print ( " iS SECOND, variable Your: ", SECOND,)
Print (" Your THIRD, variable iS: ", THIRD,)
# Note: argv things out in, unpack, all parameters in order to replicate these variables on the left
>> python ex13. py first second third
14 Exercise: Tips and passed mainly on input () function with the input format
from sys import argv
'''
PS E:\dev\code\笨方法学python3> python ex14.py Zed
Hi Zed,I'm the ex14.py script.'
I'd like to ask ypu a few questions.
Do ypu like me Zed?
>yes
Where do ypu live Zed?
>yicheng
What kind of computer do you have?
>Dell
'''
script , user_name = argv
prompt = '>'
print(f"Hi {user_name},I'm the {script} script.'")
print("I'd like to ask you a few questions.")
print(f"Do ypu like me {user_name}?")
likes = input(prompt)
print(f"Where do you live {user_name}?")
lives = input(prompt)
print("What kind of computer do you have?")
computer = input(prompt)
print(f'''
Alright, so you said {likes} about liking me.
You live in {lives}. Not sure where that is.
And you have a {computer} computer. Nice.
''')
Practice 15: read the file
txt = open(filename)
print(f"Here's your file {filename}:")
print(txt.read())
txt.close()
Exercise 16: Reading and Writing Files
close: close the file. With your editor in the "File" -> "Save" is a meaning read: read the contents of the file readline: only read text file line truncate: empty file, please be careful using this command write ( 'stuff' ): the "stuff" to write the file seek (0): the read position to the beginning of the file
Practice 17: Continue to read and write files
in_file = open(from_file) indata = in_file.read() out_file = open(to_file,'w') out_file.write(indata)
Exercise 18: Functions
Exercise 19: Functions and Variables
pytyon when defining the function with the C / C ++ is quite big difference, Python no need to define the type of parameters, defining a particular function can refer to the following:
def function(vailable1, vailable2,*):
Exercise 20: functions and files
Import the argv SYS from
Script, the argv = input_file
DEF print_all (F):
Print (reached, f.read ())
DEF rewind (F):
f.seek (0) # print with line numbers
def print_a_line (line_count, f) :
Print (line_count, f.readline ())
current_File = open (input_file) # accept parameters, open the file
Print ( "First the let's at the Whole file Print: \ the n-")
print_all (current_File) # print the file
print ( "Now apos rewind the let, kind of like a Tape. ")
rewind (current_File) # read position to the beginning of the file (in front of a position of the first character) to facilitate the subsequent read operation is not performed as the subsequent printing blank
print ( "Let apos Print Three Lines:")
current_line. 1 =
print_a_line (current_line, current_File)
print_a_line (current_line, current_File)
current_line current_line +. 1 =
current_line = current_line + 1
print_a_line(current_line, current_file)