认识
Python Strings https://developers.google.com/edu/python/strings
格式 | format
python – How do I put a variable’s value inside a string (interpolate it into the string)? – Stack Overflow
https://www.cnblogs.com/alfred0311/p/7735539.html
http://lofic.github.io/tips/python-heredoc.html
# 格式化输出 %s & %d 等
# ----------------------------------------------------------------------------- # %
print("%s %s" % ("foo", "bar"))
print("Name:%-10s Age:%08d Height:%08.2f" % ("Alfred", 25, 1.70))
# ----------------------------------------------------------------------------- # f""
name = "John"
f"Hello, {name}." # Hello, John.
f"Hello, {name:5s}." # Hello, John . # 固定宽度
# ----------------------------------------------------------------------------- # str.format()
"{name} was {place}".format(name='Louis', place='here')
"Hello, {}".format(name)
"For only {price:.2f} dollars!".format(price = 49)
截取 | str[start:end:step]
# ----------------------------------------------------------------------------- # str[start:end:step] text = "Hello, World!" print(text[2:5]) # 输出: llo print(text[:5]) # 输出: Hello print(text[7:]) # 输出: World! print(text[-6:-1]) # 输出: World # 使用步长 print(text[::2]) # 输出: Hlo ol! # 反转字符串 print(text[::-1]) # 输出: !dlroW , olleH
分割 | split()
使用字符串切割字符串
txt = "127.0.0.1:8080"
txt.split(":") # ['127.0.0.1', '8080']，默认使用空字符串分割
替换 | replace()
str = "This is string example....wow!!! this is really string"
str.replace("is", "was")
去空 | 两边去空白字符
Python Trim String – rstrip(), lstrip(), strip()）
"".strip() "".lstrip() "".rstrip()
增加宽度 | python – How to pad a string to a fixed length with spaces – Stack Overflow
'69'.rjust(5, '*') # => ***69 '69'.ljust(3, '#') # => 69# '69'.zfill(8) # => 00000069 'John'.ljust(15) # with Whitespace
长度 | 计算某个字符串长度
len("foo") # 3
为空 | 判断字符串为空
python – How to check if the string is empty? – Stack Overflow）
if not myString:
# do stuff
编码 | Base64, Endcoding and Decoding
Encoding and Decoding Base64 Strings in Python
import base64
message = "Python is fun"
message_bytes = message.encode('ascii')
base64_bytes = base64.b64encode(message_bytes)
base64_message = base64_bytes.decode('ascii')
import base64
base64_message = 'UHl0aG9uIGlzIGZ1bg=='
base64_bytes = base64_message.encode('ascii')
message_bytes = base64.b64decode(base64_bytes)
message = message_bytes.decode('ascii')
注意，如上示例，编码与解码函数需要输出字节
编码转换
urllib.parse.quote(query) # 该函数不转码斜线
urllib.parse.quote_plus(query) # 转码空格到加号的所有字符
# Unicode decode
str.encode("utf-8").decode("unicode_escape")
二进制 ⇔ 普通字符串
b'bin string'.decode('ascii')
多上字符创 | 长文本 | Heredoc | Multiline String
python – heredoc or multiline string
Multiline String in Python – GeeksforGeeks
text="""{name}
was
{place}"""
text.format(name='Louis', place='here')
# 注 1：通过 {{ 来转义 { 字符；
// --------------------------------------------------------- //
colors = ("multi-line string"
"red \n"
"blue \n"
"green \n"
"yellow \n"
)
multi-line stringred
blue
green
yellow
参考文献
How to convert ‘binary string’ to normal string in Python3?
How to encode URLs in Python
How do I treat an ASCII string as unicode and unescape the escaped characters in it in python?