2018.03.26 Python-pandas String Common methods

 import NumPy as NP
Import Pandas as PD
1 #string Common methods-strip2s = PD. Series (['Jack','Jill','Jease','Feank'])3DF = PD. DataFrame (Np.random.randn (3,2), columns=['Column A','Column B'],index=range (3))4 Print(s)5 Print(df.columns)6 7 Print('----')8 Print(S.str.lstrip (). Values)#Remove the left space9 Print(S.str.rstrip (). Values)#Remove the space on the rightTenDf.columns =Df.columns.str.strip () One Print(Df.columns)

Results:

0      Jack 1       jill2     jease 3      feankdtype:objectindex ([' Column A ', ' column B '], dtype= ' object ')----[' Jack ' J Ill ' jease ' feank ' ['  Jack ' Jill ' Jease ' Feank ']index ([' Column A ', ' column B '], dtype= ' object ')

#string Common Method-replace replacement stringDF = PD. DataFrame (Np.random.randn (3,2), columns=['Columns A','Columns B'],index = Range (3))Print(df.columns) df.columns= Df.columns.str.replace (' ','-')Print(df.columns) df.columns= Df.columns.str.replace ('-','hehe', n=1)#to replace the first one with hehe.Print(Df.columns)

Results:

Index ([' Columns A ', '  Columns B '], dtype= ' object ') index (['-columns-a ', '--columns-b '], dtype= ' object ') index ([' Hehecolumns-a ', ' hehe-columns-b '], dtype= ' object ')

#string Common methods-split, rsplit in the form of lists lists = PD. Series (['A,b,c',' the',['a,,, C'],np.nan])Print(s)Print('----')Print(S.str.split (','))Print('----')#split, similar to stringPrint(S.str.split (',') [0])#Index first RowPrint(S.str.split (','). Str[0])#first columnPrint(S.str.split (','). Str.get (1))#second column#You can use the get or [] symbol to access the elements of a split listPrint(S.str.split (',', expand=true,n=1))#N to expand the quantityPrint(S.str.rsplit (',', expand=true,n=1))#Rsplit points from right to left#Expand can extend this operation to return Dataframe#n parameter limit score#Rsplit is similar to split, which works in reverse, from the end of a string to the beginning of a stringPrint('Dataframe:') DF= PD. DataFrame ({'Key1':['A,b,c',' the',[',,,']],                   'Key2':['a-b-c','1-2-c',[',-,-,']]})Print(df['Key2'])Print(df['Key2'].str.split ('-'))

Results:
0 A,b,c
1
2 [a,,, C]
3 NaN
Dtype:object
----
0 [A, b, c]
1 [1, 2, 3]
2 NaN
3 NaN
Dtype:object
----
[' A ', ' B ', ' C ']
0 A
1 1
2 NaN
3 NaN
Dtype:object
0 b
1 2
2 NaN
3 NaN
Dtype:object
0 1
0 A B,c
1 1 2,3
2 Nan Nan
3 Nan Nan
0 1
0 A, b C
1 3
2 Nan Nan
3 Nan Nan
Dataframe
0 a-b-c
1 1-2-c
2 [,-,-,]
Name:key2, Dtype:object
0 [A, b, c]
1 [1, 2, C]
2 NaN
Name:key2, Dtype:object

#String Indexs = PD. Series (['A','b','C','Bbhello','123', Np.nan,'HJ']) DF= PD. DataFrame ({'Key1': List ('abcdef'),                   'Key2':['Hee','FV','W','Hjja','123', Np.nan]})Print(S,'\ n-----')Print(S.str[0])#take the first stringPrint(S.str[:2])#take the first 2 charactersPrint('-----')Print(df['Key2'].str[0])#STR follows the same index as the string itself

Results:

0          A1          B2          C3    Bbhello4        1235        NaN6         hjdtype:object-----0      A1      B2      C3      B4      the      hdtype:object0      A1      B2 C3 Bb4 NaN6 hjdtype:object     -----0      H1 NaN6      F2      W3      h4    Nanname:key2, Dtype:object

2018.03.26 Python-pandas String Common methods