pandas.Series.str.replace#

Series.str.replace(pat,repl,n=-1,case=None,flags=0,regex=False)[source]#

Replace each occurrence of pattern/regex in the Series/Index.

Equivalent tostr.replace() orre.sub(), depending onthe regex value.

Parameters:

patstr or compiled regex

String can be a character sequence or regular expression.

replstr or callable

Replacement string or a callable. The callable is passed the regexmatch object and must return a replacement string to be used.Seere.sub().

nint, default -1 (all)

Number of replacements to make from start.

casebool, default None

Determines if replace is case sensitive:

• If True, case sensitive (the default ifpat is a string)

• Set to False for case insensitive

• Cannot be set ifpat is a compiled regex.

flagsint, default 0 (no flags)

Regex module flags, e.g. re.IGNORECASE. Cannot be set ifpat is a compiledregex.

regexbool, default False

Determines if the passed-in pattern is a regular expression:

• If True, assumes the passed-in pattern is a regular expression.

• If False, treats the pattern as a literal string

• Cannot be set to False ifpat is a compiled regex orrepl isa callable.

Returns:

Series or Index of object

A copy of the object with all matching occurrences ofpat replaced byrepl.

Raises:

ValueError

• ifregex is False andrepl is a callable orpat is a compiledregex

• ifpat is a compiled regex andcase orflags is set

Notes

Whenpat is a compiled regex, all flags should be included in thecompiled regex. Use ofcase,flags, orregex=False with a compiledregex will raise an error.

Examples

Whenpat is a string andregex is True, the givenpatis compiled as a regex. Whenrepl is a string, it replaces matchingregex patterns as withre.sub(). NaN value(s) in the Series areleft as is:

>>>pd.Series(['foo','fuz',np.nan]).str.replace('f.','ba',regex=True)0    bao1    baz2    NaNdtype: object

Whenpat is a string andregex is False, everypat is replaced withrepl as withstr.replace():

>>>pd.Series(['f.o','fuz',np.nan]).str.replace('f.','ba',regex=False)0    bao1    fuz2    NaNdtype: object

Whenrepl is a callable, it is called on everypat usingre.sub(). The callable should expect one positional argument(a regex object) and return a string.

To get the idea:

>>>pd.Series(['foo','fuz',np.nan]).str.replace('f',repr,regex=True)0    <re.Match object; span=(0, 1), match='f'>oo1    <re.Match object; span=(0, 1), match='f'>uz2                                            NaNdtype: object

Reverse every lowercase alphabetic word:

>>>repl=lambdam:m.group(0)[::-1]>>>ser=pd.Series(['foo 123','bar baz',np.nan])>>>ser.str.replace(r'[a-z]+',repl,regex=True)0    oof 1231    rab zab2        NaNdtype: object

Using regex groups (extract second group and swap case):

>>>pat=r"(?P<one>\w+) (?P<two>\w+) (?P<three>\w+)">>>repl=lambdam:m.group('two').swapcase()>>>ser=pd.Series(['One Two Three','Foo Bar Baz'])>>>ser.str.replace(pat,repl,regex=True)0    tWO1    bARdtype: object

Using a compiled regex with flags

>>>importre>>>regex_pat=re.compile(r'FUZ',flags=re.IGNORECASE)>>>pd.Series(['foo','fuz',np.nan]).str.replace(regex_pat,'bar',regex=True)0    foo1    bar2    NaNdtype: object