Pandas之旅（六): 字符串实用方法汇总

摘要：有关字符串基本方法大家好，我又回来了之前的几期我们已经简单了解了的基础操作，但是只要涉及到数据，最常见的就是字符串类型，所以很多时候我们其实都在和字符串打交道，所以今天，我会把我自己总结的，有关字符串的常用方法分享给大家，希望能够帮到各位小

大家好，我又回来了！ 之前的几期我们已经简单了解了pandas的基础操作，但是只要涉及到数据，最常见的就是String（字符串）类型，所以很多时候我们其实都在和字符串打交道，所以今天，我会把我自己总结的，有关字符串的常用方法分享给大家，希望能够帮到各位小伙伴~

latitude = "37.24N"
longitude = "-115.81W"
"Coordinates {0},{1}".format(latitude,longitude)
>>>   "Coordinates 37.24N,-115.81W"

f"Coordinates {latitude},{longitude}"
>>>"Coordinates 37.24N,-115.81W"

"{0},{1},{2}".format(*("abc"))
>>>"a,b,c"

coord = {"latitude":latitude,"longitude":longitude}
"Coordinates {latitude},{longitude}".format(**coord)
>>>"Coordinates 37.24N,-115.81W"

class Point:
    def __init__(self,x,y):
        self.x,self.y = x,y
    def __str__(self):
        return "Point({self.x},{self.y})".format(self = self)
    def __repr__(self):
        return f"Point({self.x},{self.y})"

test_point = Point(4,2)
test_point
>>>    Point(4,2)

str(Point(4,2))
>>>"Point(4,2)"

" repr() shows the quote {!r}, while str() doesn"t:{!s} ".format("a1","a2")
>>> " repr() shows the quote "a1", while str() doesn"t:a2 "

"{:<30}".format("left aligned")
>>>"left aligned                  "

"{:>30}".format("right aligned")
>>>"                 right aligned"

"{:^30}".format("centerd")
>>>"           centerd            "

"{:*^30}".format("centerd")
>>>"***********centerd************"

"int:{0:d}, hex:{0:x}, oct:{0:o}, bin:{0:b}".format(42)
>>>"int:42, hex:2a, oct:52, bin:101010"

"{:,}".format(12345677)
>>>"12,345,677"

points = 19
total = 22
"Correct answers: {:.2%}".format(points/total)
>>>"Correct answers: 86.36%"

import datetime as dt
f"{dt.datetime.now():%Y-%m-%d}"
>>>"2019-03-27"

f"{dt.datetime.now():%d_%m_%Y}"
>>>"27_03_2019"

today = dt.datetime.today().strftime("%d_%m_%Y")
today

"27_03_2019"

"this is a  test".split()
>>>["this", "is", "a", "test"]

"do"*2
>>>"dodo"

orig_string ="Hello"
orig_string+",World"
>>>"Hello,World"

full_sentence = orig_string+",World"
full_sentence
>>>"Hello,World"

strings = ["do","re","mi"]
", ".join(strings)
>>>"do, re, mi"

"z" not in "abc"
>>> True

ord("a"), ord("#")
>>> (97, 35)

chr(97)
>>>"a"

s = "foodbar"
s[2:5]
>>>"odb"

s[:4] + s[4:]
>>>"foodbar"

s[:4] + s[4:] == s
>>>True

t=s[:]
id(s)
>>>1547542895336

id(t)
>>>1547542895336

s is t
>>>True

s[0:6:2]
>>>"fob"

s[5:0:-2]
>>>"ado"

s = "tomorrow is monday"
reverse_s = s[::-1]
reverse_s
>>>"yadnom si worromot"

s.capitalize()
>>>"Tomorrow is monday"

s.upper()
>>>"TOMORROW IS MONDAY"

s.title()
>>>"Tomorrow Is Monday"

s.count("o")
>>> 4

"foobar".startswith("foo")
>>>True

"foobar".endswith("ar")
>>>True

"foobar".endswith("oob",0,4)
>>>True

"foobar".endswith("oob",2,4)
>>>False

"My name is yo, I work at SG".find("yo")
>>>11

# If can"t find the string, return -1
"My name is ya, I work at Gener".find("gent")
>>>-1

# Check a string if consists of alphanumeric characters
"abc123".isalnum()
>>>True

"abc%123".isalnum()
>>>False

"abcABC".isalpha()
>>>True

"abcABC1".isalpha()
>>>False

"123".isdigit()
>>>True

"123abc".isdigit()
>>>False

"abc".islower()
>>>True

"This Is A Title".istitle()
>>>True

"This is a title".istitle()
>>>False

"ABC".isupper()
>>>True

"ABC1%".isupper()
>>>True

"foo".center(10)
>>>"   foo    "

"   foo bar baz    ".strip()
>>>"foo bar baz"

"   foo bar baz    ".lstrip()
>>>"foo bar baz    "

"   foo bar baz    ".rstrip()
>>>"   foo bar baz"

"foo abc foo def fo  ljk ".replace("foo","yao")
>>>"yao abc yao def fo  ljk "

"www.realpython.com".strip("w.moc")
>>>"realpython"

"www.realpython.com".strip("w.com")
>>>"realpython"

"www.realpython.com".strip("w.ncom")
>>>"realpyth"

", ".join(["foo","bar","baz","qux"])
>>>"foo, bar, baz, qux"

list("corge")
>>>["c", "o", "r", "g", "e"]

":".join("corge")
>>>"c:o:r:g:e"

"www.foo".partition(".")
>>>("www", ".", "foo")

"foo@@bar@@baz".partition("@@")
>>>("foo", "@@", "bar@@baz")

"foo@@bar@@baz".rpartition("@@")
>>>("foo@@bar", "@@", "baz")

"foo.bar".partition("@@")
>>>("foo.bar", "", "")

# By default , rsplit split a string with white space
"foo bar adf yao".rsplit()
>>>["foo", "bar", "adf", "yao"]

"foo.bar.adf.ert".split(".")
>>>["foo", "bar", "adf", "ert"]

"foo
bar
adfa
lko".splitlines()
>>>["foo", "bar", "adfa", "lko"]

除了我以上总结的这些，还有太多非常实用的方法，大家可以根据自己的需求去搜索啦！

我把这一期的ipynb文件和py文件放到了Github上，大家如果想要下载可以点击下面的链接：

Github仓库地址： https://github.com/yaozeliang/pandas_share

希望大家能够继续支持我，完结，撒花