Part of the root of all evil -python

1. String formatted output

% Placeholders:

% S - Canton declared string type placeholder% d% i-- escaped become common integer %%%

    %s ,%d, %%

msg = '%s，学习进度5%%'
print(msg%(input("name:")))

%s -- 占字符串的位置
%d -- 占整型的位置
%% -- 转义（把占位转换成普通的%号）

name = input("name")
print(f"alex{name},{'aaa'}")

% () No more, no less, correspondence

name = input("name:")
age = input("age:")
sex = input("sex:")
job = input("job:")
hobby = input("hobby:")

print(msg%(input("name:"),input("age:"),input("sex:"),input("job:"),input("hobby:)

f "{}" braces are generally placed inside the content string variable in single quotes

3.6 or later is required to use

2.while cycle

while key conditions: (infinite loop)

Loop

Conditions Terminator Cycle

break terminates the current cycle

continue out of this cycle, the next cycle continues

3. Operator

Arithmetic operators:

Contains + - * / ** //%

Assignment operator:

= += -= *= **= %= //=

Logical operators:

and (with - and) or (or) not (non - not)

1 and 0  # and是两边都是真的时候才是真，只要有一边是假就取假
    0 and 1
print(1 and 9)   #and 运算 两边都是真的时候取and后边的内容
print(False and 0) #and 运算 两边都是假的时候取and前边的内容

Comparison Operators

== ！= > < >= <=

Member operator

in the absence not in

4. encoding

ASCII code - the first computer code is not supported by Chinese

GBK-- GB:

English one byte

Chinese 2 bytes

Unicode- Unicode:

English 2 bytes

Chinese 4 bytes

utf-8- most popular encoding

English byte

Owen 2 bytes

Asian 3 bytes

Unit conversion:

1B=8b

1024B=1KB

1024KB=1MB

1024MB=1GB

1024GB=1TB

Part of the root of all evil -python

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