How do I change format of biblatex bibliography entries?

Question

My journal articles are not appearing correctly in my bibliography. For example, this journal article:

@article{biernacki1981snowball,
  title={Snowball sampling: Problems and techniques of chain referral sampling},
  author={Biernacki, Patrick and Waldorf, Dan},
  journal={Sociological methods \& research},
  volume={10},
  number={2},
  pages={141--163},
  year={1981},
  publisher={SAGE Publications Sage CA: Los Angeles, CA}
}

appears as

Biernacki, P. and Waldorf, D. (1981). “Snowball sampling: Problems and techniques
    of chain referral sampling”. In: Sociological methods & research
    10.2, pp. 141–163.

How do I change '. In:' to ',' ? I.e get:

Biernacki, P. and Waldorf, D. (1981). “Snowball sampling: Problems and techniques
    of chain referral sampling”, Sociological methods & research
    10.2, pp. 141–163.

The journal should be in italics in which mind he did ask is again actually the network too much earlier.

The thing is too big for a MWE but I use:

\usepackage{bibentry} 
\usepackage[style=authoryear-ibid,firstinits,backend=bibtex,sorting=nyt,natbib=true, maxbibnames=99,maxcitenames=2, uniquelist=false, uniquename=false]{biblatex}
\DeclareNameAlias{sortname}{family-given}
\addbibresource{example.bib}

Answer 1

To get rid of the "in:" for good and make it only a comma for all entry types, go with

\renewbibmacro*{in:}{%
  \setunit{\addcomma\space}}

If you only want the ". In:" to disappear for @articles you'll want

\renewbibmacro*{in:}{%
  \ifentrytype{article}
    {\setunit{\addcomma\space}}
    {\printtext{%
       \bibstring{in}\intitlepunct}}}

where there will be a full stop before the "in:" for all other entry types

or

\renewbibmacro*{in:}{%
  \setunit{\addcomma\space}%
  \ifentrytype{article}
    {}
    {\printtext{%
       \bibstring{in}\intitlepunct}}}

where all types get a comma at roundabout the position of the "in:" (or where it would be if it were present).

---

Old answer kept in case it might be useful for someone else.

\renewbibmacro*{in:}{%
  \setunit{\addcomma\space}%
  \printtext{%
    \bibstring{in}\intitlepunct}}

will replace all full stops/periods before the "In:" with a comma resulting in ", in:" being output instead. This changes all "in:"s - @article as well as @incollection, @inbook and @inproceedings

---

With

\renewcommand*{\newunitpunct}{\addcomma\space}

the punctuation before the "in:" as well as a lot of other punctuation can be changed from a full stop to a comma. \newunitpunct is the generic go-to punctuation command in case no special punctuation is defined.