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Python |
PHP |
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enter |
input() |
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output |
print() |
echo、var_dump() 、print、print_r |
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quit |
exit() |
exit()、die() |
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linux runs directly |
add comments before code #!/usr/bin/env python3
Permission settings $ chmod a+x filename.py |
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Format |
indent |
curly braces |
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case |
sensitive |
Not sensitive |
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indentation |
Tab and 4-space indentation are not allowed to mix |
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translation area |
r'' |
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newline |
print('''content''') |
\n |
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Boolean operations |
and、or、not |
&& || ! |
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division |
Ordinary division /, floor division (round down) // |
/ |
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Integer and floating point numbers |
Python's integers have no size limit Python's floating-point numbers have no size limit, but if they exceed a certain range, they are directly represented as inf (infinite) |
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String to bytes |
string.encode('ascii') string.encode('utf-8') |
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bytes to string |
string.decode('ascii') string.decode('utf-8') In bytes, bytes that cannot be displayed as ASCII characters are displayed with \x##. Error when transcoding directly string.decode('utf-8',errors = 'ignore') |
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string length |
len () bytes will count the number of bytes when using len() |
strlen() |
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utf-8 transcoding tag |
file header #!/usr/bin/env python3 # -*- coding: utf-8 -*- |
header('content-type:text/html;charset=utf-8'); |
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formatted output |
print('%s,%s' % ('tony', 'joe')) %% Express%
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Python |
PHP |
sorted set list |
一种有序的集合,可以随时添加和删除其中的元素,元素类型不限制 可以list里面嵌套list list = [1,2,3,4,5] |
类似redis中的有序集合 |
集合长度计算 |
len() |
lsize(key) |
索引访问 |
list[0],索引范围为0—(len(list)-1) 索引为-1时表示最后一个元素,反过来也同样不允许越界 |
lindex(key,0) |
尾部添加 |
list.append(value) |
rpush(key,value) |
尾部删除 |
list.pop() |
rpop(key) |
指定索引添加 |
list.insert(index,value) |
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指定索引删除 |
list.pop(index) |
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集合排序 |
list.sort() 执行后直接改变list |
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集合嵌套 |
嵌套集合使用len()时候,只计算第一层元素数量,但是可以先用索引找到子元素,然后继续使用子元素的索引获得元素 |
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元组tuple |
一种不能修改的有序列表 tuple = (1,2,3,4,5) 定义的时候必须确定元素,如果是空的,直接使用tuple = ()表示 特殊情况:tuple中包含list,尽管list中内容可变,但是tuple的资源指向不会变化 注意:单元素的时候如果想表示元组必须加个逗号! tuple = (1,),否则按小括号计算,定义为普通变量 |
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Python |
PHP |
条件判断 依靠缩进判断执行顺序
:代替{}
elif简化表达 |
a = 100 if a>100: print(a) elif a==100: print(0) else: print(-a) |
a = 100; if (a>100) { print(a); }elseif (a=100) { print(0); }else{ print(-a) } |
input结合条件判断 |
s = input('birth: ') birth = int(s) if birth < 2000: print('00前') else: print('00后') input输入的是字符串,直接与数值比较的时候会报错! |
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for循环 |
a = ["aaa","bbb","ccc"] for s in a: print(s)
b = [1,2,3,4,5] sum = 0 for num in b: sum = sum + num print(sum) |
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while循环 |
sum = 0 a = 1 while a<=100: sum = sum + a a = a + 1 print(sum) |
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break |
结束循环 |
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continue |
结束本次循环,执行下个循环 |
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range生成整数序列 |
list(range(num)) 可以生成0—num-1的整数list |
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Python |
PHP |
字典dict |
键值对方式存储 dict = {"a":1,"b":2,"c":3} 查找和插入的速度极快,不会随着key的增加而变慢;需要占用大量的内存,内存浪费多。 空间换时间 dict的key必须是不可变对象。 |
类似json |
dict获取 key不存在的时候会报错 |
print(dict["a"]) 或 print(dict.get(key,defaultValue)) 不设置默认值的时候取不到返回none |
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判断key是否存在 |
print(key in dict) |
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dict数据插入 key一样的时候,后插入替换前面 |
dict["d"] = 4 |
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dict数据删除 |
dict.pop(key) |
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无序集合set |
一组key的集合,不存储value, key不重复,重复的时候会自动过滤 以list作为输入集合 list = [1,3,2] set = set(list) print(set) |
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集合新增 |
set.add(key) 重复时能运行,不生效,自动去重 |
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集合删除 |
set.remove(key) |
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set交集和并集 |
交集set1 & set2 并集set1 | set2 |
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