str = "abcd   efg， gfe    dcba\
hijk   lmn"
print(str.replace("\r\n"," "))

str = "abcd   efg， gfe    dcba\
hijk   lmn"
print(str.replace('/r/n',' '))

分别运行后结果都是

abcd efg， gfe dcbahijk lmn

​